Recent Advances in Characterization Techniques for the Interface in Carbon Nanotube-Reinforced Polymer Nanocomposites

Chen, Junjie; Gao, Xuhui; Xu, Deguang

doi:https://doi.org/10.1155/2019/5268267

Advances in Materials Science and Engineering

On this page

Abstract Introduction Conflicts of Interest Acknowledgments References Copyright Related Articles

Special Issue

Microscopic Techniques in Material Science: Current Trends in the Area of Blends, Composites, and Hybrid Materials

View this Special Issue

Review Article | Open Access

Volume 2019 | Article ID 5268267 | https://doi.org/10.1155/2019/5268267

Recent Advances in Characterization Techniques for the Interface in Carbon Nanotube-Reinforced Polymer Nanocomposites

Junjie Chen,¹Xuhui Gao,¹and Deguang Xu¹

Guest Editor: Alena Šišková

Received06 Dec 2018

Revised24 Feb 2019

Accepted06 Mar 2019

Published01 Apr 2019

Abstract

The current state of characterization techniques for the interface in carbon nanotube-reinforced polymer nanocomposites is reviewed. Different types of interfaces that exist within the nanocomposites are summarized, and current efforts focused on understanding the interfacial properties and interactions are reviewed. The emerging trends in characterization techniques and methodologies for the interface are presented, and their strengths and limitations are summarized. The intrinsic mechanism of the interactions at the interface between the carbon nanotubes and the polymer matrix is discussed. Special attention is given to research efforts focused on chemical functionalization of carbon nanotubes. The benefits and disadvantages associated with covalent and noncovalent functionalization methods are evaluated, respectively. Various techniques used to characterize the properties of the interface are extensively reviewed. How the mechanical and thermal properties of the nanocomposites depend on the physical and chemical nature of the interface is also discussed. Better understanding and design of the interface at the atomic level could become the forefront of research in the polymer community. Potential problems going to be solved are finally highlighted.

1. Introduction

Since the discovery of carbon nanotubes and, in particular, the realization of their unique performance [1–4], much effort has been devoted to develop advanced nanocomposites with carbon nanotubes as reinforcement [5–10]. Full understanding of the excellent behavior of carbon nanotube-reinforced nanocomposites requires knowledge of the interactions at the interface between the carbon nanotubes and the matrix [11–16]. There are no essential differences between such a requirement and that for conventional fiber-reinforced composites, but the characteristic length scale of the reinforcement varies from micrometer to nanometer. The fundamental challenge for applied research on carbon nanotube-reinforced nanocomposites can be illustrated by the electron microscope images shown in Figure 1, where multiwalled carbon nanotubes (decade nanometers in diameter) are deposited on the surface of carbon fibers (a few microns in diameter) in yarn bundles (a few millimeters in diameter) [17, 18]. The variation in the characteristic length scale of the reinforcement presents both new challenges and significant advantages in the development of fabrication techniques for carbon nanotube-reinforced nanocomposites [19–22] and the development of characterization techniques for such nanocomposites [23–28]. The nanometer scale of the reinforcement represents a significant challenge in the fundamental research of mechanics, since the interfacial interactions at the atomic-scale must be accounted for [29–32].

Various attempts have been made in recent years to develop ceramic-matrix and metal-matrix nanocomposites with carbon nanotubes as reinforcement [33–36], but much more attention has been focused on the development of carbon nanotube-reinforced polymer nanocomposites [37–40]. The outstanding physical and mechanical properties of this new form of carbon have led to significant advances in the development of such nanocomposites for both functional and structural applications [41–44]. However, the potential of carbon nanotubes as reinforcement for polymers has not yet been fully realized, especially in the resulting mechanical properties [17, 20]. The application of carbon nanotube-reinforced polymer nanocomposites depends strongly on how to effectively address the issues and challenges associated with the fundamental properties of the interface between the carbon nanotubes and the polymer matrix [45, 46].

Increasing attention is focused on the properties of the interface in carbon nanotube-reinforced polymer nanocomposites. From the point of view of micromechanics, stress is transferred across such an interface [47, 48]. In addition, the mechanical performance of the nanocomposites depends critically on both the stress transfer across the interface and the shear strength of the interface [49–52]. Furthermore, the thermal resistance of the interface is the most critical factor influencing the thermal performance of the nanocomposites [53–56]. Consequently, knowledge of the properties of the interface becomes particularly essential to the development of carbon nanotube-reinforced polymer nanocomposites. To unlock the full potential of carbon nanotubes and to further improve the overall performance of such nanocomposites, it is important to understand the fundamental properties of the interface [57–60].

Research on carbon nanotube-reinforced polymer nanocomposites is an emerging area, which was first introduced by Ajayan and coworkers [61, 62]. Their work certainly represents a significant milestone towards the development of the nanocomposites and, together with other early work [63, 64], clearly demonstrates that the extraordinary properties inherent to carbon nanotubes can be transferred into the polymer matrix efficiently. Since then, the literature related to the nanocomposites is growing explosively, always accompanied by scientific debates [65–70]. Significant insights have been gained through nanotechnology research, with over 20 papers each day currently appearing in relation to carbon nanotube-reinforced polymer nanocomposites alone, as shown in Figure 2. One of the most interesting avenues of research involves manipulation of the chemistry of carbon nanotubes [71–74], which offers great opportunities for developing multifunctional polymer nanocomposites with the ability to tailor the properties of the interface [75, 76]. As yet, the physical and chemical nature of the interface, along with its influence on the bulk properties of carbon nanotube-reinforced polymer nanocomposites, remains a poorly understood area of research.

Significant progress has been made in understanding the nature of the interface in carbon nanotube-reinforced polymer nanocomposites. Unfortunately, there are only several review articles focused on the topic available in the literature. Chen et al. [77] have provided an overview of the current state of the properties of the interface in carbon nanotube-reinforced polymer nanocomposites. However, full understanding of the nature of the interface requires knowledge of both interfacial properties and characterization techniques [78]. Both complement each other naturally, be short of one cannot, making it easier to understand the nature of the interface. It is therefore of great significance to provide a literature review about the characterization techniques for the interface, in addition to interfacial properties. This review is devoted to characterization techniques for the interface in carbon nanotube-reinforced polymer nanocomposites. Particular emphasis is placed on how to determine the properties of the interface at the nanometer scale for such nanocomposites.

2. Techniques for Interface Characterization

Measurement and control of the strength of the interface are important for developing carbon nanotube-reinforced polymer nanocomposites with tailored interfacial structures and properties [79, 80]. To fully realize the benefits of carbon nanotubes and to further improve the overall performance of the nanocomposites, it is essential to obtain accurate information about the microscopic structure and properties of the interface [81, 82]. Electron microscope techniques such as scanning electron microscopy [83, 84] and transmission electron microscopy [85, 86] have been extensively used for the general visual identification of carbon nanotube-reinforced polymer nanocomposites. Additionally, optical microscope techniques such as confocal laser scanning microscopy are effective in evaluating the quality of the dispersion of carbon nanotube in a polymer matrix [87–90]. However, the above microscope techniques are usually not sufficient enough to characterize the properties of the interface at the atomic level. High-resolution transmission electron microscopy could achieve the atomic resolution and is being used widely in the field of the nanocomposites to provide more information about the microscopic structure of the interface [91–94].

Atomic force microscopy [95, 96] and Raman spectroscopy [97, 98] have served to quantitatively characterize the properties of the interface. Atomic force microscopy may be the preferred technique for characterization of the interface due to its advantages for high-precision and high-sensitivity measurements [99, 100]. This microscope technique can also serve as a means to elucidate the properties of the interface in polymer nanocomposites [101, 102]. Two particularly powerful approaches to characterize the properties of the interface are the pull-out method [103] and the peeling method [104]. Attempts have also been made in recent years to develop more convenient ways such as Raman spectroscopy to directly assess the properties of the interface [97, 98].

2.1. Atomic Force Microscopy

In developing carbon nanotube-reinforced polymer nanocomposites, it is essential to focus on the properties of the interface, as they determine the efficiency of interfacial load transfer [41–44] and can significantly influence the resulting mechanical performance [1–4]. The strength of the interface can serve as a quantitative indicator in evaluating the mechanical properties of the nanocomposites. This physical parameter is usually measured through individual carbon nanotube pull-out tests using atomic force microscopy [99, 100]. Individual carbon nanotube pull-out tests are ideal measurements to quantitatively characterize the interfacial load transfer between carbon nanotubes and the polymer matrix. Such experiments involve the use of the probes of atomic force microscopy ex situ, or are carried out in situ within a chamber of scanning electron microscopy. Based on such nano-pull-out test technology, several nanomechanical methods are being developed and tested for the nanocomposites [58, 99, 103, 105–112]. For example, carbon nanotubes can be bonded to the probe of an atomic force microscopy, embedded in a polymer melt, and then pulled out from the matrix after solidification [103, 105, 106], as shown in Figure 3. Partially embedded carbon nanotubes were observed on the fatigue fracture surface in a polymer matrix and pulled out by a nanomanipulator [58, 99, 107].

(a)

(b)

(c)

(d)

(e)

(f)

Figure 3

Schematic diagram of an individual carbon nanotube pull-out experiment and scanning electron microscope images of one representative individual carbon nanotube pull-out test: (a) a tip fixed to the cantilever of an atomic force microscope approaches the free end of an individual carbon nanotube embedded within a polymer matrix in a controlled way, (b) such a free end has been attached to the tip of the cantilever by means of electron beam-induced deposition of platinum, (c) the carbon nanotube has been pulled out from the polymer matrix completely, and (d)–(f) three scanning electron microscope images of the individual carbon nanotube pull-out test, corresponding to the schematic diagrams illustrated in (a)–(c), respectively. The lower right image in (f) is a zoom-in view of the carbon nanotube after being pulled out. Each of the scale bars represents 500 nm (adapted with permission from reference [99]; copyright 2015, Elsevier Ltd).

Barber et al. [103, 105, 106] attached an individual multiwalled carbon nanotube to the sharp tip of an atomic force microscope. The carbon nanotube was then pulled from a polymer matrix, while the critical force necessary to remove such a carbon nanotube was recorded by the atomic force microscope. Shear strength of the interface [103] and fracture energy for the interface [105] were predicted by measuring the critical pull-out force and the carbon nanotube embedment length. Poggi et al. [113, 114] measured the interfacial adhesion between specific functional groups and the outer surface of an individual single-walled carbon nanotube using a chemically modified chemical force microscope, where the tip of the cantilever of an atomic force microscope was chemically modified. The interaction characteristics of the interface were then measured using this chemical force microscopy [113, 114].

However, there are still some critical issues that need to be addressed before performing such an individual carbon nanotube pull-out test using atomic force microscopy [108]. Images may be limited by misalignment during the cantilever-tip assembly load. Additionally, the intensity of the force signal recorded by atomic force microscopy is based on the assessment of cantilever stiffness as well as the determination of cantilever deflection from low-resolution scanning electron microscope images, both of which may eventually lead to considerable errors [103, 105, 106]. Finally, the embedment depth of an individual carbon nanotube cannot be controlled and measured easily using this nano-pull-out test technology. To observe the embedded portion of such a carbon nanotube after the process of a nano-pull-out test, Nie et al. [101] developed a carbon nanotube-polymer nanobridge structure in a polymer film, as described below.

The strength of the interface can serve as an indicator of interfacial load transfer for the nanocomposites, as it can greatly affect their effective mechanical performance. Unfortunately, inevitable entanglement or kinks of carbon nanotubes inside a polymer matrix would complicate the characterization of the interface as probed and measured by individual carbon nanotube pull-out tests. To observe an embedded carbon nanotube before or during the process of a nano-pull-out test, there is a need for a beam of electrons with high energy in a transmission electron microscope or a scanning electron microscope [115–118], which may damage or cross-link the polymer matrix and the interface. To address this issue, Nie et al. [101] developed a controllable method to measure the strength of the interface with the help of an individual nanobridge in a suspended polymer film and proposed an effective way to evaluate the efficiency of interfacial load transfer, as illustrated in Figure 4. Such a microscopic structure is constructed on the basis of the self-assembly of multiwalled carbon nanotubes in liquid flow and the phase separation of polymer blends and the ductile fracture of such blends after thermal and chemical treatment, as shown in Figure 5(a). The microscopic structure of such a nanobridge can be characterized by a nanomechanical method, by which the force applied to the individual multiwalled carbon nanotube in a suspended state in the transverse direction leads to the pull-out force in the axial direction, as shown in Figures 5(b)–5(d). An atomic force microscope is used to apply such transverse force in a controlled way to the suspended carbon nanotube to produce the force in the axial direction. Such axial force can be applied to pull a segment of the embedded part of an individual carbon nanotube out of a polymer matrix. The pull-out force in the axial direction can be obtained through the control signal recorded by the deflection of the cantilever. The average strength of the interface formed by an individual multiwalled carbon nanotube and a poly(methyl methacrylate) matrix is about 48 MPa, measured by using this method [101]. Such a controllable method can be used to measure the strength of the interface for the nanocomposites due to the ability to form an image of the embedded portion of an individual carbon nanotube and to the high-resolution imaging during the loading process [101]. It is important to note that this technique is only applicable to the polymers with the ability to form a phase separation structure.

Figure 4

(a and b) Schematic diagram of the pull-out process applied to an individual carbon nanotube suspended within a free-standing polymer thin film using an atomic force microscope. Schematic diagram of the fabrication process of a suspended holey film as being formed from a polymer blend: (c) a hydrophobic polymer thin film coated on the surface of a hydrophilic glass slide using a dip-coating method, (d) release of such a film from the glass slide by water, (e and f) transfer of the film to a grid made of copper, and (g) hole-opening using cyclohexane as a solvent and then using a heat treatment method (adapted with permission from reference [101]; copyright 2017, Elsevier Ltd).

(a)

(b)

(c)

(d)

Figure 5

(a) Schematic diagram of the formation and evolution process of a nanobridge structure for an individual carbon nanotube-polymer nanocomposite, (b) scanning electron microscope images of such a carbon nanotube suspended across a hole in a layer of the polymer blend film made of poly(methyl methacrylate) and polystyrene using a self-assembly method (left) and the holes opened by using thermal and solvent treatment techniques after adding a second layer of poly(methyl methacrylate) film (right), (c) transmission electron microscope image of the nanobridge structure in a polymer film, and (d) atomic force microscope image of an individual, suspended carbon nanotube with two ends embedded in a poly(methyl methacrylate) matrix (adapted with permission from reference [101]; copyright 2017, Elsevier Ltd).

Atomic force microscopy also provides an efficient way to gain insight into the adhesive mechanics of an individual carbon nanotube peeled from a polymer matrix by means of the peeling method described in the literature [104]. Strus et al. [104] used such a method to attach an individual multiwalled carbon nanotube to the peeling probe of an atomic force microscope, as illustrated in Figure 6. The critical force required to peel the multiwalled carbon nanotube off the surface of a polymer matrix was recorded, and the fracture energy of the interface was then quantitatively measured. This method has the ability to measure the properties of the interface, but it is incapable of measuring the interfacial energy per unit area [104].

(a)

(b)

(c)

2.2. Raman Spectroscopy

Raman spectroscopy can serve as a powerful tool to characterize the properties of the interface by utilizing the unique electronic and vibrational structure of carbon nanotube-reinforced polymer nanocomposites [119–130]. This spectroscopic technique was found to be more effective in revealing the level of disorder and defect sites on the surface of carbon nanotubes [129, 130]. Raman spectroscopy is one of the most effective techniques used to analyze the microscopic mechanism of interfacial load transfer for the nanocomposites [63]. There is a shift in Raman frequency with the stress or strain applied to the nanocomposites [131, 132]. If such a stress is transferred to the carbon nanotubes across the interface, the Raman peak shifts by a few cm⁻¹. The shift in Raman frequency is linear with the strain applied to the nanocomposites, and the slope of the Raman shift-strain response curve is dependent on the properties of the polymer matrix as well as the degree of alignment of carbon nanotubes [133, 134].

Raman spectroscopy can provide information about the elastic modulus of polymer-based nanocomposites, alignment and dispersion of carbon nanotubes, interfacial load transfer, and interfacial interaction characteristics [135–140]. Such interactions are usually reflected by a shift in Raman frequency or a peak width change [91, 141]. However, there are some disadvantages associated with this spectroscopic technique [135–140]. For example, since the diameter of the Raman laser spot is much larger than that of an individual carbon nanotube, the Raman signal is averaged over carbon nanotubes in all directions [91, 141].

Earlier publications associated a shift in Raman frequency to a lower frequency or to a higher frequency from the peak about 2700 cm⁻¹ with tensile strain and compressive strain in a carbon nanotube-reinforced polymer nanocomposite [64, 142]. Ruan et al. [143, 144] monitored load transfer across the interface from an ultrahigh molecular weight polyethylene matrix to multiwalled carbon nanotubes, with a shift in Raman frequency at 2691 cm⁻¹. They also suggested four regimes of strain behavior, as outlined in Table 1. Another work [145] related a shift in Raman frequency at 1594 cm⁻¹ with the compressive strain in single-walled carbon nanotubes embedded in an epoxy matrix.

3. Interactions at the Interface

It is of great significance to understand the interactions at the interface [146–149]. Knowledge of such interactions is necessary to gain insight into the properties of the nanocomposites [146]. An optimum interfacial interaction is a critical step in achieving the full potential of carbon nanotubes [147], which has become a primary goal of this emerging area of research [146–149].

Chemical functionalization of carbon nanotubes has proved effective in improving the characteristics of interfacial interactions and the performance of the resulting nanocomposites [150–153]. Chemical functionalization of carbon nanotubes, such as wrapping of polymer around carbon nanotubes [154], as illustrated schematically in Figure 7, or introducing covalent interfacial bonding [155], has been achieved. In general, covalent and noncovalent interfacial interactions [156–159] are the two main chemical functionalization methods.

(a)

(b)

(c)

Figure 7

Single-walled carbon nanotube wrapped by three poly(9,9-dioctylfluorenyl-2,7-diyl) chains with different geometries: (a) polymer chains aligned to the axis of the carbon nanotube and (b) periodic helical conformation. The polymer chains are represented by different colors: red, blue, and yellow. (c) The side chains of the polymer covered by the solvent system that contains enough toluene molecules. The toluene molecules are represented by light gray (adapted with permission from reference [154]; copyright 2011, American Chemical Society).

3.1. Covalent Interactions

Covalent chemical functionalization of carbon nanotubes involves the covalent attachment of functional groups onto either the sidewalls or ends of carbon nanotubes [160, 161]. The open ends of carbon nanotubes can be stabilized by hydroxide and carboxylic acid groups, and the sidewalls of carbon nanotubes can be chemically modified by reactive elements [42]. For example, nitric acid treatment was reported to successfully oxidize the surface of carbon nanotubes as detected by Fourier transform infrared spectroscopy [162, 163]. Covalent chemical functionalization of carbon nanotubes can also be accomplished through diazonium salts [164] or Diels–Alder reactions [165].

Recently, an extensive review of various covalent functionalization methods of nanoparticles by means of tailoring surface properties to improve their wettability and compatibility with polymer matrices has been made by Mosnáčková et al. [166]. Different methods of surface modification by polymer chains have been described in detail with some examples of functionalization of various types of nanoparticles to obtain advanced properties of polymer nanocomposites. Various polymerization mechanisms have been discussed in detail. The current state of various grafting methods has also been summarized. The effect of introduced functional groups on the properties of carbon nanotubes and polymer nanocomposites has recently been reviewed by Wei et al. [167].

Covalent functionalization can enhance the interactions at the interface effectively, making it possible to significantly improve the performance of the resulting nanocomposites [16, 42, 49]. Gojny et al. [168, 169] gave direct evidence of significant interactions existed at the interface, as illustrated in Figure 8. Amino acids were successfully used to modify carbon nanotubes by heating the oxidized carbon nanotubes with excess triethylenetetramine. Their works clearly demonstrated that a covalent bond was formed at the interface through introducing functional groups [168, 169]. The chemically modified carbon nanotubes were completely covered with an epoxy matrix, as indicated by the transmission electron microscope images of functionalized carbon nanotubes in the polymer matrix in Figure 8. Upon the expansion of the crack formed in the polymer matrix heated by a beam of electrons from a transmission electron microscope, the outer layer of an individual, functionalized multiwalled carbon nanotube was fractured and embedded in an epoxy matrix, as shown in Figure 8(d). In contrast, the inner shells of the functionalized multiwalled carbon nanotube, which were bounded together by the relatively weak van der Waals forces between these shells, were pulled out from the polymer matrix through a sword-in-sheath mechanism [168, 169].

(a)

(b)

(c)

(d)

(e)

Figure 8

Transmission electron microscope images of an individual, functionalized multiwalled carbon nanotube in an epoxy matrix. (a) Chemically modified carbon nanotube covered by the polymer matrix completely, indicating improved interactions at the interface through a covalent chemical functionalization method. (b and c) Fracture toughness improved by such carbon nanotubes through bridging microcracks and pores in the polymer matrix. (d and e) Evidence of improved interactions at the interface through pull-out tests (adapted with permission from references [168, 169]; copyrights 2003 and 2004, Elsevier Ltd).

Covalent chemical functionalization has been proved to be an effective way for improving the properties of the interface [168, 169], such as the efficiency of interfacial load transfer, making it possible to significantly improve the properties of carbon nanotube-reinforced polymer nanocomposites [168, 169]. However, this functionalization method would introduce structural defects into the surface of carbon nanotubes, thus lowering their intrinsic properties [170, 171]. As a consequence, there is often a tradeoff between the properties of carbon nanotubes and those of the interface. In addition, covalent functionalization may cause severe disruption of the electronic network and structure of carbon nanotubes [170, 171], which may lead to decreased performance of the final nanocomposites.

3.2. Noncovalent Interactions

Alternatively, noncovalent functionalization of carbon nanotubes can serve to improve the properties of the interface. This functionalization method utilizes interactions and van der Waals forces by adsorption of polymers [172–175]. Noncovalent functionalization of carbon nanotubes is particularly attractive, since it does not deteriorate their intrinsic properties [176–179]. This functionalization method mainly involves the polymer wrapping of carbon nanotubes. Wrapping is typically denoted as the enveloping of the surface of carbon nanotubes by polymers. Three possible multihelical wrapping conformations can be found in the work of O’Connell et al. [175], as shown in Figure 9. Recent studies demonstrated that single-walled carbon nanotubes can be wrapped in a number of adsorbing polymers, such as biopolymers such as DNA [180, 181], block copolymers [182, 183], and semiconjugated polymers [184, 185].

(a)

(b)

(c)

Polymer wrapping of carbon nanotubes has proven to be quite effective in improving the properties of the interface, making it possible to greatly improve the properties of carbon nanotube-reinforced polymer nanocomposites [186, 187]. For example, interfacial interactions can be significantly improved by using conjugated polymers with a specific molecular configuration [187]. Yang et al. [187] utilized molecular dynamics to investigate the physical interactions at the interface for different polymer matrices. Their modeling work suggested that polymers with a main chain containing aromatic functionalities hold great promise for the noncovalent binding of carbon nanotubes into the structure of the nanocomposites, as shown in Figure 10, since these aromatic rings are able to provide strong interactions at the interface. Such polymers could serve as a building block for amphiphilic copolymers not only to enhance the interactions at the interface but also to improve the mechanical performance of the resulting nanocomposites. Polymer wrapping of carbon nanotubes also holds great promise for the manipulation and organization of carbon nanotubes into ordered structures and even for their noncovalent functionalization [187].

Unfortunately, the possible mechanisms underlying the noncovalent interactions have not yet been fully understood [146]. It has been found that wrapping of single-walled carbon nanotubes by polymers is a general interfacial phenomenon [175]. Furthermore, recent molecular dynamics studies suggested that such interactions depend strongly on the specific structure of polymer matrices, and the effect of polymer affinity and flexibility is important [188–193]. For example, stiff-chain polymers tend to wrap around single-walled carbon nanotubes in a more distinct conformation than polymers with a high degree of flexibility in the backbone structure [188, 189], as shown in Figure 11, making it possible to improve the interfacial properties, such as the intermolecular interaction energy at the interface, for the resulting nanocomposites.

Noncovalent functionalization offers a number of advantages for improving the properties of the interface and the performance of the resulting nanocomposites, without affecting the intrinsic properties of carbon nanotubes [194–197]. However, it is often difficult to achieve the desirable strength of the interface so as to ensure the load transfer across the interface with high efficiency for carbon nanotube-reinforced nanocomposites [198–201].

4. Characterization of Interfacial Mechanical Properties

The nature of the interface is of particular importance to the interfacial stress transfer and the consequent improvement in the mechanical properties for the nanocomposites [202, 203]. For example, good interfacial bonding is necessary to ensure the load transfer across the interface with high efficiency, which is a necessary condition for further development of the nanocomposites with high mechanical performance [204, 205]. Over the past few decades, it has become increasingly clear that considerable modification of the properties of the interface can be an effective way to improve the overall mechanical performance for the nanocomposites [206–209].

The work of Wong et al. [204] has shown that the interfacial shear stress measured for multiwalled carbon nanotube-reinforced polymer nanocomposites is larger than that measured for conventional microfiber-reinforced composites by orders of magnitude. Furthermore, there were no broken carbon nanotubes based on an analysis of the interfacial morphology measured by both transmission electron microscopy and scanning electron microscopy for carbon nanotube-reinforced epoxy nanocomposites [204], indicating that the load transfer across the interface was not sufficient to fracture the multiwalled carbon nanotubes. In contrast, recent experiments have demonstrated that the failure of multiwalled carbon nanotube-reinforced polymer nanocomposites appears to arise from mechanical fracture of the polymer matrix and from the pull-out of such carbon nanotubes from the polymer matrix [106, 210, 211].

Qian et al. [212] characterized the properties of the polystyrene nanocomposites reinforced with multiwalled carbon nanotubes to investigate the behavior of the load transfer across the interface and deformation mechanisms of the nanocomposites. Ex situ mechanical tensile tests on films of the nanocomposites shown that after adding 1.0% by weight of carbon nanotubes, the tensile strength is improved by about 25.0% and the elastic stiffness is increased by about 36–42%, indicating that there are considerable load transfer across the interface and significant improvement in the mechanical performance of the polymer. In this context, an external load can be transferred from the polymer matrix to carbon nanotubes effectively. Furthermore, in situ transmission electron microscopy provided essential information about the interfacial bonding and deformation mechanisms of the nanocomposites described above, as illustrated in Figure 12. As for commercial carbon fiber-reinforced polymer composites, a fracture of carbon nanotubes and crack bridging by carbon nanotubes were observed during pull-out tests. In contrast, multiwalled carbon nanotubes pulled out from the polymer matrix, while less fracture was observed, as shown in Figure 12. Furthermore, there are strong interactions at the interface [212], as evidenced by the significant improvement in the mechanical performance of the nanocomposites given above. Qian et al. [212] also demonstrated that 10% by weight of carbon fibers in the previous work of Tibbetts and McHugh [213] was required to achieve the same effectiveness of the improvement in the elastic modulus of the nanocomposites containing only 1.0% by weight of multiwalled carbon nanotubes by utilizing short-fiber composite theory.

(a)

(b)

Figure 12

In situ transmission electron microscopy images of crack nucleation and propagation induced by thermal stresses in a polystyrene thin film reinforced with multiwalled carbon nanotubes. (a) Such a crack propagates along relatively low density regions of carbon nanotubes or along weak interfaces. (b) The multiwalled carbon nanotubes tend to align and bridge the crack wake, and subsequently to break and/or pull out from the polymer matrix (adapted with permission from reference [212]; copyright 2000, American Institute of Physics).

The force required to pull an individual multiwalled carbon nanotube out from a polyethylenebutene matrix was measured by atomic force microscopy [103]. The mean interfacial shear strength of 47 MPa was sufficiently high, indicating that there exists covalent bonding at the interface. Furthermore, the chain of the polymer close to the interface behaved differently from its bulk. A sheathing layer of a polymer on pulled out multiwalled carbon nanotubes, i.e., an interfacial region, was imaged [107], as shown in Figure 13, which gave direct evidence of significant interfacial interactions. In addition, an additional increase was observed in the diameter of the polymer sheathing layer after chemical functionalization of carbon nanotubes, possibly indicating chemical augmentation of interfacial bonding. Chemically functionalized carbon nanotubes could improve the interactions at the interface [214, 215]. Orders of magnitude improvement in interfacial shear strength would be required to achieve more efficient reinforcement for the nanocomposites [216]. While optimization of the interfacial properties for the mechanical reinforcement is still poorly understood at the nanoscale, the recent evidence available clearly suggests that chemical functionalization can be effective for such reinforcement [217], as shown in Figure 14, and this method appears to be a major focus of improvement in the performance of the nanocomposites.

(a)

(b)

(c)

(d)

(e)

(f)

Figure 13

Direct evidence of multiple polymer sheathing layers in a polycarbonate nanocomposite reinforced with multiwalled carbon nanotubes, confirmed by the nanomanipulation contact experiments carried out under a scanning electron microscope. (a) Initial contact with an individual, protruding multiwalled carbon nanotube by a tip of the cantilever of an atomic force microscope. (b) The inner structure of the nanocomposite has become detached partially from the outer polymer sheathing layer in the process of bending. (c) Such a structure is clamped to a tip of the cantilever of an atomic force microscope by electron beam-induced deposition, and the outer polymer sheathing layer balls up. (d) The inner structure has been broken close to the fracture surface of the nanocomposite during tensile loading. (e) The fracture broken end of the coated multiwalled carbon nanotube provides clear evidence of a double polymer sheathing layer. (f) Higher magnification image of the fracture broken end of the coated multiwalled carbon nanotube (adapted with permission from reference [107]; Copyright 2003, American Chemical Society).

(a)

(b)

Figure 14

(a) Morphology of the quasistatically fractured surfaces characterized by a scanning electron microscope for neat epoxy and chemically modified epoxy composites. (b) Morphology of the quasistatic fracture surface characterized by a scanning electron microscope for an epoxy-polyol hybrid nanocomposite reinforced with multiwalled carbon nanotubes, illustrating a bridging phenomenon as well as the pull-out process of multiwalled carbon nanotubes from the polymer matrix (adapted with permission from reference [217]; copyright 2014, Elsevier Ltd).

Strong interfacial interactions are usually necessary to ensure successful stress transfer across such an interface. An effective strategy for the improvement in the interactions at the interface is chemical functionalization by which polymer chains are attached onto the surface of carbon nanotubes. However, the unique mechanical performance of carbon nanotubes is dependent on their specific chemical structure [218, 219]. Covalent functionalization would introduce internal stresses and atomic defects into the surface of carbon nanotubes [220, 221], thereby deteriorating their inherent mechanical properties. On the other hand, noncovalent functionalization offers an alternative strategy for regulating the properties of the interface [222, 223]. Such a strategy does retain the intrinsic properties of carbon nanotubes, but, unfortunately, interfacial stress transfer might not be so effective in the treatment for the nanocomposites. It is usually difficult for this modification strategy to improve the interfacial properties efficiently [224, 225], and considerable improvements remain to be exploited.

5. Characterization of Interfacial Thermal Properties

The thermal resistance of the interface, also known as Kapitza resistance, plays an important role in determining the thermal properties of the nanocomposites [226, 227]. The interfacial thermal resistance has been investigated both experimentally and theoretically [228–237]. The recent results measured and predicted for the interfacial thermal resistance of the nanocomposites are summarized in Table 2. Such resistance is typically on the order of magnitude of 10⁻⁸ m²·K/W.

Since transport of heat in carbon nanotube-reinforced polymer nanocomposites is by way of elastic vibrations of the lattice, heat transfer based on this mechanism is limited by the elastic scattering of acoustic phonons at lattice defects [238, 239]. As a consequence, the interfacial thermal resistance is caused by the scattering of acoustic phonons across the interface [238, 239]. It is therefore of great significance to gain insight into such a thermal property for the nanocomposites, making it possible to further improve their overall thermal performance [53, 54]. To address issues associated with the interfacial thermal resistance, it is usually necessary to use the method of molecular dynamics simulations to understand the interfacial thermal resistance and to evaluate the benefits and disadvantages associated with new ways to reduce such resistance [227, 229, 231].

Large thermal resistance at the interface has emerged as a significant challenge, and such a technical issue has not been addressed yet. Much effort has been devoted to estimate the interfacial thermal resistance [227], as well as to evaluate the effect of chemical functionalization and the role of interfacial interactions [240, 241]. Unfortunately, the influence of interfacial properties on the thermal conductivity of the nanocomposites has not yet been fully understood. Chemically functionalized multiwalled carbon nanotubes were found to have the potential to realize carbon nanotube-reinforced polymer nanocomposites with improved thermal properties because this type of carbon nanotubes can provide unique structure advantages [240, 241].

Covalent functionalization of carbon nanotubes have proven to be very effective in improving the interfacial thermal conductance for carbon nanotube-reinforced polymer nanocomposites [242, 243], eventually leading to their improved overall thermal performance [228]. For example, a significant improvement in interfacial thermal conductance was reported as large as one order of magnitude for the nanocomposites by means of this chemical method [229]. Molecular dynamics simulations can serve as a powerful tool to explore the effect of covalent functionalization of carbon nanotubes on the thermal properties of the resulting nanocomposites [229, 231], as particularly well illustrated in Figure 15. Covalent functionalization can significantly improve the overall thermal performance for carbon nanotube-reinforced polymer nanocomposites due to a great increase in the thermal conductance of the interface [229, 231]. However, excessive chemical functionalization will damage the intrinsic thermal properties of carbon nanotubes [244–247].

(a)

(b)

(c)

Figure 15

(a) An individual single-walled carbon nanotube with short end-grafted chains. (b) Schematic diagram of an individual single-walled carbon nanotube functionalized with crosslinker diethylenetoluenediamine and embedded in an epoxy matrix. Carbon nanotubes are rendered in cyan. The color scheme for the functionalized diethylenetoluenediamine molecule (red: hydrogen and carbon atoms contained in methyl groups, yellow: nitrogen atoms, and blue: carbon atoms contained in benzene rings. (c) Schematic diagram of a single-walled carbon nanotube-epoxy nanocomposite with different interfacial thicknesses. The nanocomposite exists in an epoxy environment, with the carbon nanotube as heat source and the interfacial region close to the polymer matrix as heat sink (adapted with permission from references [229, 231]; copyright 2006, Elsevier Ltd. Copyright 2012, TMS.

6. Concluding Remarks

Characterization is a fundamental process in the field of materials science, without which no scientific understanding of engineering materials could be ascertained. Characterization of the interface in carbon nanotube-reinforced polymer nanocomposites has been reviewed. Special emphasis is placed on how to determine the properties of the interface at the nanometer scale.

Tremendous research efforts are ongoing to characterize the properties of the interface in the polymer community. The state of research on the chemical functionalization of carbon nanotubes has been presented, followed by considerable details given over to the mechanical and thermal properties being pursued or envisioned in this emerging area. Various emerging characterization techniques used to determine the microscopic structure and properties of the interface are summarized.

New characterization techniques and methodologies are constantly emerging. In particular, the advent of atomic force microscopy in recent decades has revolutionized the field of carbon nanotube-reinforced polymer nanocomposites, allowing the imaging and analysis of the structures of the interface on much smaller scales than was previously possible, resulting in a significant increase in the level of understanding as to why different carbon nanotube-polymer interfaces show different bulk properties and behaviors. Atomic force microscopy can be combined with a variety of optical microscopy and spectroscopy techniques, thus further expanding its applicability.

Progress towards carbon nanotube-reinforced polymer nanocomposites will require continued development of characterization techniques, providing potential for tailoring the properties of the interface. The characteristic scale of the carbon nanotube reinforcement presents significant challenges to the development of methods for characterizing the properties of the interface. To address the issues associated with interfacial properties, it will be essential to understand the critical nature of the interface, develop accurate nanomechanics-based models, elucidate the interactions at the interface, and acquire knowledge of the relationship between nanocomposite properties and interfacial optimization, aiming at improving the performance of the nanocomposites effectively.

Carbon nanotubes pose both tremendous opportunities and significant new challenges for the development of fundamentally new polymer-based nanocomposites. Understanding the essence of the nanometer-scale reinforcement mechanism for the nanocomposites certainly warrants further experimental and theoretical research. Multidisciplinary research efforts will be required to bridge the gap in the existing knowledge between technological developments and fundamental understanding. There has never been a more exciting time to be involved in the field with new fundamental discoveries to be made regularly. It is hoped that this review would contribute to the development of this emerging area in some small way and would stimulate new research enthusiasm to enrich the content of an increasingly exciting discipline.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

Acknowledgments

This work was supported by the National Natural Science Foundation of China (no. 51506048).

References

S. Iijima, “Helical microtubules of graphitic carbon,” Nature, vol. 354, no. 6348, pp. 56–58, 1991.
View at: Publisher Site | Google Scholar
S. Iijima and T. Ichihashi, “Single-shell carbon nanotubes of 1-nm diameter,” Nature, vol. 363, no. 6430, pp. 603–605, 1993.
View at: Publisher Site | Google Scholar
D. S. Bethune, C. H. Kiang, M. S. de Vries et al., “Cobalt-catalysed growth of carbon nanotubes with single-atomic-layer walls,” Nature, vol. 363, no. 6430, pp. 605–607, 1993.
View at: Publisher Site | Google Scholar
K. Tanaka and S. Iijima, Carbon Nanotubes and Grapheme, Elsevier Ltd., Amsterdam, Netherlands, 2nd edition, 2014.
View at: Publisher Site
K. M. Liew, M. F. Kai, and L. W. Zhang, “Carbon nanotube reinforced cementitious composites: an overview,” Composites Part A: Applied Science and Manufacturing, vol. 91, no. 1, pp. 301–323, 2016.
View at: Publisher Site | Google Scholar
R. Bhatia, K. Kumari, R. Rani, A. Suri, U. Pahuja, and D. Singh, “A critical review of experimental results on low temperature charge transport in carbon nanotubes based composites,” Reviews in Physics, vol. 3, pp. 15–25, 2018.
View at: Publisher Site | Google Scholar
D. Janas and B. Liszka, “Copper matrix nanocomposites based on carbon nanotubes or graphene,” Materials Chemistry Frontiers, vol. 2, no. 1, pp. 22–35, 2018.
View at: Publisher Site | Google Scholar
D. R. Paul and L. M. Robeson, “Polymer nanotechnology: nanocomposites,” Polymer, vol. 49, no. 15, pp. 3187–3204, 2008.
View at: Publisher Site | Google Scholar
D. Han, H. Mei, S. Xiao, K. G. Dassios, and L. Cheng, “A review on the processing technologies of carbon nanotube/silicon carbide composites,” Journal of the European Ceramic Society, vol. 38, no. 11, pp. 3695–3708, 2018.
View at: Publisher Site | Google Scholar
A. Azarniya, A. Azarniya, S. Sovizi et al., “Physicomechanical properties of spark plasma sintered carbon nanotube-reinforced metal matrix nanocomposites,” Progress in Materials Science, vol. 90, pp. 276–324, 2017.
View at: Publisher Site | Google Scholar
M. Ding, Y. Tang, and A. Star, “Understanding interfaces in metal-graphitic hybrid nanostructures,” Journal of Physical Chemistry Letters, vol. 4, no. 1, pp. 147–160, 2013.
View at: Publisher Site | Google Scholar
G. A. Rance, D. H. Marsh, S. J. Bourne, T. J. Reade, and A. N. Khlobystov, “van der Waals interactions between nanotubes and nanoparticles for controlled assembly of composite nanostructures,” ACS Nano, vol. 4, no. 8, pp. 4920–4928, 2010.
View at: Publisher Site | Google Scholar
Z. P. Michael, W. Shao, D. C. Sorescu, R. W. Euler, S. C. Burkert, and A. Star, “Probing biomolecular interactions with gold nanoparticle-decorated single-walled carbon nanotubes,” Journal of Physical Chemistry C, vol. 121, no. 38, pp. 20813–20820, 2017.
View at: Publisher Site | Google Scholar
K. Bhattacharya, S. P. Mukherjee, A. Gallud et al., “Biological interactions of carbon-based nanomaterials: from coronation to degradation,” Nanomedicine: Nanotechnology, Biology and Medicine, vol. 12, no. 2, pp. 333–351, 2016.
View at: Publisher Site | Google Scholar
J. Gao, B. Zhao, M. E. Itkis et al., “Chemical engineering of the single-walled carbon nanotube-nylon 6 interface,” Journal of the American Chemical Society, vol. 128, no. 23, pp. 7492–7496, 2006.
View at: Publisher Site | Google Scholar
Y. Ni, H. Han, S. Volz, and T. Dumitricaˇ, “Nanoscale azide polymer functionalization: a robust solution for suppressing the carbon nanotube-polymer matrix thermal interface resistance,” Journal of Physical Chemistry C, vol. 119, no. 22, pp. 12193–12198, 2015.
View at: Publisher Site | Google Scholar
E. T. Thostenson, C. Li, and T.-W. Chou, “Nanocomposites in context,” Composites Science and Technology, vol. 65, no. 3-4, pp. 491–516, 2005.
View at: Publisher Site | Google Scholar
E. T. Thostenson, W. Z. Li, D. Z. Wang, Z. F. Ren, and T. W. Chou, “Carbon nanotube/carbon fiber hybrid multiscale composites,” Journal of Applied Physics, vol. 91, no. 9, pp. 6034–6037, 2002.
View at: Publisher Site | Google Scholar
A. Alshaghel, S. Parveen, S. Rana, and R. Fangueiro, “Effect of multiscale reinforcement on the mechanical properties and microstructure of microcrystalline cellulose-carbon nanotube reinforced cementitious composites,” Composites Part B: Engineering, vol. 149, pp. 122–134, 2018.
View at: Publisher Site | Google Scholar
S. I. Yengejeh, S. A. Kazemi, and A. Öchsner, “Carbon nanotubes as reinforcement in composites: a review of the analytical, numerical and experimental approaches,” Computational Materials Science, vol. 136, pp. 85–101, 2017.
View at: Publisher Site | Google Scholar
A. M. Beese, X. Wei, S. Sarkar et al., “Key factors limiting carbon nanotube yarn strength: exploring processing-structure-property relationships,” ACS Nano, vol. 8, no. 11, pp. 11454–11466, 2014.
View at: Publisher Site | Google Scholar
V. M. Candelario, R. Moreno, Z. Shen, F. Guiberteau, and A. L. Ortiz, “Liquid-phase assisted spark-plasma sintering of SiC nanoceramics and their nanocomposites with carbon nanotubes,” Journal of the European Ceramic Society, vol. 37, no. 5, pp. 1929–1936, 2017.
View at: Publisher Site | Google Scholar
V. Lutz, J. Duchet-Rumeau, N. Godin, F. Smail, F. Lortie, and J. F. Gérard, “Ex-PAN carbon fibers vs carbon nanotubes fibers: from conventional epoxy based composites to multiscale composites,” European Polymer Journal, vol. 106, pp. 9–18, 2018.
View at: Publisher Site | Google Scholar
H. Deng, J. Yi, C. Xia, and Y. Yi, “Mechanical properties and microstructure characterization of well-dispersed carbon nanotubes reinforced copper matrix composites,” Journal of Alloys and Compounds, vol. 727, pp. 260–268, 2017.
View at: Publisher Site | Google Scholar
A. E. Moumen, M. Tarfaoui, and K. Lafdi, “Mechanical characterization of carbon nanotubes based polymer composites using indentation tests,” Composites Part B: Engineering, vol. 114, pp. 1–7, 2017.
View at: Publisher Site | Google Scholar
T. K. Truong, Y. Lee, and D. Suh, “Multifunctional characterization of carbon nanotube sheets, yarns, and their composites,” Current Applied Physics, vol. 16, no. 9, pp. 1250–1258, 2016.
View at: Publisher Site | Google Scholar
H. S. Bedi, M. Tiwari, and P. K. Agnihotri, “Quantitative determination of size and properties of interphases in carbon nanotube-based multiscale composites,” Carbon, vol. 132, pp. 181–190, 2018.
View at: Publisher Site | Google Scholar
H. Wang, Z.-H. Zhang, H.-M. Zhang, Z.-Y. Hu, S.-L. Li, and X.-W. Cheng, “Novel synthesizing and characterization of copper matrix composites reinforced with carbon nanotubes,” Materials Science and Engineering: A, vol. 696, pp. 80–89, 2017.
View at: Publisher Site | Google Scholar
B. D. Jensen, G. M. Odegard, J.-W. Kim, G. Sauti, E. J. Siochi, and K. E. Wise, “Simulating the effects of carbon nanotube continuity and interfacial bonding on composite strength and stiffness,” Composites Science and Technology, vol. 166, pp. 10–19, 2018.
View at: Publisher Site | Google Scholar
X. Chen, J. Tao, J. Yi et al., “Enhancing the strength of carbon nanotubes reinforced copper matrix composites by optimizing the interface structure and dispersion uniformity,” Diamond and Related Materials, vol. 88, pp. 74–84, 2018.
View at: Publisher Site | Google Scholar
H. Wang, Z.-H. Zhang, Z.-Y. Hu et al., “Improvement of interfacial interaction and mechanical properties in copper matrix composites reinforced with copper coated carbon nanotubes,” Materials Science and Engineering: A, vol. 715, pp. 163–173, 2018.
View at: Publisher Site | Google Scholar
C. Yi, S. Bagchi, C. M. Dmuchowski et al., “Direct nanomechanical characterization of carbon nanotubes–titanium interfaces,” Carbon, vol. 132, pp. 548–555, 2018.
View at: Publisher Site | Google Scholar
A. R. Boccaccini, J. Cho, T. Subhani, C. Kaya, and F. Kaya, “Electrophoretic deposition of carbon nanotube-ceramic nanocomposites,” Journal of the European Ceramic Society, vol. 30, no. 5, pp. 1115–1129, 2010.
View at: Publisher Site | Google Scholar
E. Zapata-Solvas, D. Gómez-García, and A. Domínguez-Rodríguez, “Towards physical properties tailoring of carbon nanotubes-reinforced ceramic matrix composites,” Journal of the European Ceramic Society, vol. 32, no. 12, pp. 3001–3020, 2012.
View at: Publisher Site | Google Scholar
S. R. Bakshi, D. Lahiri, and A. Agarwal, “Carbon nanotube reinforced metal matrix composites–a review,” International Materials Reviews, vol. 55, no. 1, pp. 41–64, 2010.
View at: Publisher Site | Google Scholar
A. V. Radhamani, H. C. Lau, and S. Ramakrishna, “CNT-reinforced metal and steel nanocomposites: a comprehensive assessment of progress and future directions,” Composites Part A: Applied Science and Manufacturing, vol. 114, pp. 170–187, 2018.
View at: Publisher Site | Google Scholar
H. Wang and Z. Bao, “Conjugated polymer sorting of semiconducting carbon nanotubes and their electronic applications,” Nano Today, vol. 10, no. 6, pp. 737–758, 2015.
View at: Publisher Site | Google Scholar
P. S. Goh, A. F. Ismail, and B. C. Ng, “Directional alignment of carbon nanotubes in polymer matrices: contemporary approaches and future advances,” Composites Part A: Applied Science and Manufacturing, vol. 56, pp. 103–126, 2014.
View at: Publisher Site | Google Scholar
X. Wang, S.-C. Wong, Y. J. Jung, and K.-T. Wan, “Measuring interfacial adhesion of carbon nanotube bundles and electrospun polymer fibers,” Langmuir, vol. 33, no. 44, pp. 12592–12595, 2017.
View at: Publisher Site | Google Scholar
O. A. Bârsan, G. G. Hoffmann, L. G. J. van der Ven, and G. de With, “Single-walled carbon nanotube networks: the influence of individual tube-tube contacts on the large-scale conductivity of polymer composites,” Advanced Functional Materials, vol. 26, no. 24, pp. 4377–4385, 2016.
View at: Publisher Site | Google Scholar
Z. Spitalsky, D. Tasis, K. Papagelis, and C. Galiotis, “Carbon nanotube-polymer composites: chemistry, processing, mechanical and electrical properties,” Progress in Polymer Science, vol. 35, no. 3, pp. 357–401, 2010.
View at: Publisher Site | Google Scholar
V. D. Punetha, S. Rana, H. J. Yoo et al., “Functionalization of carbon nanomaterials for advanced polymer nanocomposites: a comparison study between CNT and graphene,” Progress in Polymer Science, vol. 67, pp. 1–47, 2017.
View at: Publisher Site | Google Scholar
C. Pramanik, D. Nepal, M. Nathanson et al., “Molecular engineering of interphases in polymer/carbon nanotube composites to reach the limits of mechanical performance,” Composites Science and Technology, vol. 166, pp. 86–94, 2018.
View at: Publisher Site | Google Scholar
Y. Liu and S. Kumar, “Polymer/carbon nanotube nano composite fibers-A review,” ACS Applied Materials & Interfaces, vol. 6, no. 9, pp. 6069–6087, 2014.
View at: Publisher Site | Google Scholar
S. K. Kumar, B. C. Benicewicz, R. A. Vaia, and K. I. Winey, “50th anniversary perspective: are polymer nanocomposites practical for applications?” Macromolecules, vol. 50, no. 3, pp. 714–731, 2017.
View at: Publisher Site | Google Scholar
J. Winey, J. F. Douglas, F. W. Starr et al., “Current issues in research on structure-property relationships in polymer nanocomposites,” Polymer, vol. 51, no. 15, pp. 3321–3343, 2010.
View at: Publisher Site | Google Scholar
J. N. Coleman, U. Khan, W. J. Blau, and Y. K. Gun’ko, “Small but strong: a review of the mechanical properties of carbon nanotube-polymer composites,” Carbon, vol. 44, no. 9, pp. 1624–1652, 2006.
View at: Publisher Site | Google Scholar
J. N. Coleman, U. Khan, and Y. K. Gun’ko, “Mechanical reinforcement of polymers using carbon nanotubes,” Advanced Materials, vol. 18, no. 6, pp. 689–706, 2006.
View at: Publisher Site | Google Scholar
K. S. Khare, F. Khabaz, and R. Khare, “Effect of carbon nanotube functionalization on mechanical and thermal properties of cross-linked epoxy-carbon nanotube nanocomposites: role of strengthening the interfacial interactions,” ACS Applied Materials & Interfaces, vol. 6, no. 9, pp. 6098–6110, 2014.
View at: Publisher Site | Google Scholar
N. Ning, T. Mi, G. Chu et al., “A quantitative approach to study the interface of carbon nanotubes/elastomer nanocomposites,” European Polymer Journal, vol. 102, pp. 10–18, 2018.
View at: Publisher Site | Google Scholar
M. Yoonessi, M. Lebrón-Colón, D. Scheiman, and M. A. Meador, “Carbon nanotube epoxy nanocomposites: the effects of interfacial modifications on the dynamic mechanical properties of the nanocomposites,” ACS Applied Materials & Interfaces, vol. 6, no. 19, pp. 16621–16630, 2014.
View at: Publisher Site | Google Scholar
P. Katti, S. Bose, and S. Kumar, “Tailored interface resulting in improvement in mechanical properties of epoxy composites containing poly(ether ether ketone) grafted multiwall carbon nanotubes,” Polymer, vol. 102, pp. 43–53, 2016.
View at: Publisher Site | Google Scholar
Z. Han and A. Fina, “Thermal conductivity of carbon nanotubes and their polymer nanocomposites: a review,” Progress in Polymer Science, vol. 36, no. 7, pp. 914–944, 2011.
View at: Publisher Site | Google Scholar
H. Chen, V. V. Ginzburg, J. Yang et al., “Thermal conductivity of polymer-based composites: fundamentals and applications,” Progress in Polymer Science, vol. 59, pp. 41–85, 2016.
View at: Publisher Site | Google Scholar
M. K. Hassanzadeh-Aghdam and M. J. Mahmoodi, “Micromechanical modeling of thermal conducting behavior of general carbon nanotube-polymer nanocomposites,” Materials Science and Engineering: B, vol. 229, pp. 173–183, 2018.
View at: Publisher Site | Google Scholar
S. Hida, T. Hori, T. Shiga, J. Elliott, and J. Shiomi, “Thermal resistance and phonon scattering at the interface between carbon nanotube and amorphous polyethylene,” International Journal of Heat and Mass Transfer, vol. 67, pp. 1024–1029, 2013.
View at: Publisher Site | Google Scholar
R. E. Gorga, K. K. S. Lau, K. K. Gleason, and R. E. Cohen, “The importance of interfacial design at the carbon nanotube/polymer composite interface,” Journal of Applied Polymer Science, vol. 102, no. 2, pp. 1413–1418, 2006.
View at: Publisher Site | Google Scholar
X. Chen, M. Zheng, C. Park, and C. Ke, “Direct Measurements of the mechanical strength of carbon nanotube-poly(methyl methacrylate) interfaces,” Small, vol. 9, no. 19, pp. 3345–3351, 2013.
View at: Publisher Site | Google Scholar
P.-H. Wang, S. Sarkar, P. Gulgunje, N. Verghese, and S. Kumar, “Fracture mechanism of high impact strength polypropylene containing carbon nanotubes,” Polymer, vol. 151, pp. 287–298, 2018.
View at: Publisher Site | Google Scholar
K. K. Ghuman and T. Fujigaya, “Electronic structure of a polybenzimidazole-wrapped single-wall carbon nanotube,” Journal of Physical Chemistry C, vol. 122, no. 28, pp. 15979–15985, 2018.
View at: Publisher Site | Google Scholar
P. M. Ajayan, O. Stephan, C. Colliex, and D. Trauth, “Aligned carbon nanotube arrays formed by cutting a polymer resin-nanotube composite,” Science, vol. 265, no. 5176, pp. 1212–1214, 1994.
View at: Publisher Site | Google Scholar
P. M. Ajayan, “Aligned carbon nanotubes in a thin polymer film,” Advanced Materials, vol. 7, no. 5, pp. 489–491, 1995.
View at: Publisher Site | Google Scholar
H. D. Wagner, O. Lourie, Y. Feldman, and R. Tenne, “Stress-induced fragmentation of multiwall carbon nanotubes in a polymer matrix,” Applied Physics Letters, vol. 72, no. 2, pp. 188–190, 1998.
View at: Publisher Site | Google Scholar
L. S. Schadler, S. C. Giannaris, and P. M. Ajayan, “Load transfer in carbon nanotube epoxy composites,” Applied Physics Letters, vol. 73, no. 26, pp. 3842–3844, 1998.
View at: Publisher Site | Google Scholar
S. V. Ahir, Y. Y. Huang, and E. M. Terentjev, “Polymers with aligned carbon nanotubes: active composite materials,” Polymer, vol. 49, no. 18, pp. 3841–3854, 2008.
View at: Publisher Site | Google Scholar
M. J. Green, N. Behabtu, M. Pasquali, and W. W. Adams, “Nanotubes as polymers,” Polymer, vol. 50, no. 21, pp. 4979–4997, 2009.
View at: Publisher Site | Google Scholar
M. T. Byrne and Y. K. Gun’ko, “Recent advances in research on carbon nanotube-polymer composites,” Advanced Materials, vol. 22, no. 15, pp. 1672–1688, 2010.
View at: Publisher Site | Google Scholar
T. Ji, Y. Feng, M. Qin, and W. Feng, “Thermal conducting properties of aligned carbon nanotubes and their polymer composites,” Composites Part A: Applied Science and Manufacturing, vol. 91, no. 1, pp. 351–369, 2016.
View at: Publisher Site | Google Scholar
G. Pal and S. Kumar, “Modeling of carbon nanotubes and carbon nanotube-polymer composites,” Progress in Aerospace Sciences, vol. 80, pp. 33–58, 2016.
View at: Publisher Site | Google Scholar
M. Kaseem, K. Hamad, and Y. G. Ko, “Fabrication and materials properties of polystyrene/carbon nanotube (PS/CNT) composites: a review,” European Polymer Journal, vol. 79, pp. 36–62, 2016.
View at: Publisher Site | Google Scholar
D. Tasis, N. Tagmatarchis, A. Bianco, and M. Prato, “Chemistry of carbon nanotubes,” Chemical Reviews, vol. 106, no. 3, pp. 1105–1136, 2006.
View at: Publisher Site | Google Scholar
S. W. Kim, T. Kim, Y. S. Kim et al., “Surface modifications for the effective dispersion of carbon nanotubes in solvents and polymers,” Carbon, vol. 50, no. 1, pp. 3–33, 2012.
View at: Publisher Site | Google Scholar
K. Adachi and Y. Tsukahara, “Surface modification of carbon nanotubes by anionic approach,” Current Opinion in Chemical Engineering, vol. 11, pp. 106–113, 2016.
View at: Publisher Site | Google Scholar
M. Adamska and U. Narkiewicz, “Fluorination of carbon nanotubes–a review,” Journal of Fluorine Chemistry, vol. 200, pp. 179–189, 2017.
View at: Publisher Site | Google Scholar
S. B. Jagtap, V. D. Patil, K. Suresh et al., “Functionalized carbon nanotube reinforced polymer nanocomposite microcapsules with enhanced stiffness,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 550, pp. 82–89, 2018.
View at: Publisher Site | Google Scholar
R. Vijayan, A. Ghazinezami, S. R. Taklimi, M. Y. Khan, and D. Askari, “The geometrical advantages of helical carbon nanotubes for high-performance multifunctional polymeric nanocomposites,” Composites Part B: Engineering, vol. 156, pp. 28–42, 2019.
View at: Publisher Site | Google Scholar
J. Chen, L. Yan, W. Song, and D. Xu, “Interfacial characteristics of carbon nanotube-polymer composites: a review,” Composites Part A: Applied Science and Manufacturing, vol. 114, pp. 149–169, 2018.
View at: Publisher Site | Google Scholar
S. Bagchi, A. Harpale, and H. B. Chew, “Interfacial load transfer mechanisms in carbon nanotube-polymer nanocomposites,” Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol. 474, no. 2216, Article ID 20170705, 2018.
View at: Publisher Site | Google Scholar
J. Chen, Y.-Y. Shi, J.-H. Yang, N. Zhang, T. Huang, and Y. Wang, “Improving interfacial adhesion between immiscible polymers by carbon nanotubes,” Polymer, vol. 54, no. 1, pp. 464–471, 2013.
View at: Publisher Site | Google Scholar
N. Taloub, L. Liu, N. Rahoui, M. Hegazy, and Y. Huang, “Grafting multi-walled carbon nanotubes (MWCNTs) into PIPD fiber for enhancing mechanical and interfacial performance,” Polymer Testing, vol. 75, pp. 344–349, 2019, In Press.
View at: Publisher Site | Google Scholar
Y. Li and G. D. Seidel, “Multiscale modeling of the interface effects in CNT-epoxy nanocomposites,” Computational Materials Science, vol. 153, pp. 363–381, 2018.
View at: Publisher Site | Google Scholar
R. Chawla and S. Sharma, “Molecular dynamics simulation of carbon nanotube pull-out from polyethylene matrix,” Composites Science and Technology, vol. 144, pp. 169–177, 2017.
View at: Publisher Site | Google Scholar
J. Z. Kovacs, K. Andresen, J. R. Pauls et al., “Analyzing the quality of carbon nanotube dispersions in polymers using scanning electron microscopy,” Carbon, vol. 45, no. 6, pp. 1279–1288, 2007.
View at: Publisher Site | Google Scholar
W. Li, S. T. Buschhorn, K. Schulte, and W. Bauhofer, “The imaging mechanism, imaging depth, and parameters influencing the visibility of carbon nanotubes in a polymer matrix using an SEM,” Carbon, vol. 49, no. 6, pp. 1955–1964, 2011.
View at: Publisher Site | Google Scholar
D. Qian and E. C. Dickey, “In-situ transmission electron microscopy studies of polymer-carbon nanotube composite deformation,” Journal of Microscopy, vol. 204, no. 1, pp. 39–45, 2001.
View at: Publisher Site | Google Scholar
B. A. Newcomb, L. A. Giannuzzi, K. M. Lyons et al., “High resolution transmission electron microscopy study on polyacrylonitrile/carbon nanotube based carbon fibers and the effect of structure development on the thermal and electrical conductivities,” Carbon, vol. 93, pp. 502–514, 2015.
View at: Publisher Site | Google Scholar
M. Ilčíková, M. Danko, M. Doroshenko et al., “Visualization of carbon nanotubes dispersion in composite by using confocal laser scanning microscopy,” European Polymer Journal, vol. 79, pp. 187–197, 2016.
View at: Publisher Site | Google Scholar
F. Zhou, D. Xing, B. Wu, S. Wu, Z. Ou, and W. R. Chen, “New insights of transmembranal mechanism and subcellular localization of noncovalently modified single-walled carbon nanotubes,” Nano Letters, vol. 10, no. 5, pp. 1677–1681, 2010.
View at: Publisher Site | Google Scholar
T. Kashiwagi, J. Fagan, J. F. Douglas et al., “Relationship between dispersion metric and properties of PMMA/SWNT nanocomposites,” Polymer, vol. 48, no. 16, pp. 4855–4866, 2007.
View at: Publisher Site | Google Scholar
B. E. Smith, H. Yazdani, and K. Hatami, “Three-dimensional imaging and quantitative analysis of dispersion and mechanical failure in filled nanocomposites,” Composites Part A: Applied Science and Manufacturing, vol. 79, pp. 23–29, 2015.
View at: Publisher Site | Google Scholar
Y. Gao, L. Li, P. Tan, L. Liu, and Z. Zhang, “Application of Raman spectroscopy in carbon nanotube-based polymer composites,” Chinese Science Bulletin, vol. 55, no. 35, pp. 3978–3988, 2010.
View at: Publisher Site | Google Scholar
F. Solá, Z. H. Xia, M. Lebrón-Colón, and M. A. Meador, “Transmission electron microscopy of single wall carbon nanotube/polymer nanocomposites: a first-principles study,” Physica Status Solidi (RRL)–Rapid Research Letters, vol. 6, no. 8, pp. 349–351, 2012.
View at: Publisher Site | Google Scholar
Z. Jin, X. Sun, G. Xu, S. H. Goh, and W. Ji, “Nonlinear optical properties of some polymer/multi-walled carbon nanotube composites,” Chemical Physics Letters, vol. 318, no. 6, pp. 505–510, 2000.
View at: Publisher Site | Google Scholar
T.-M. Wu and Y.-W. Lin, “Doped polyaniline/multi-walled carbon nanotube composites: preparation, characterization and properties,” Polymer, vol. 47, no. 10, pp. 3576–3582, 2006.
View at: Publisher Site | Google Scholar
O. A. Bârsan, G. G. Hoffmann, L. G. J. van der Ven, and G. de With, “Quantitative conductive atomic force microscopy on single-walled carbon nanotube-based polymer composites,” ACS Applied Materials & Interfaces, vol. 8, no. 30, pp. 19701–19708, 2016.
View at: Publisher Site | Google Scholar
M. Rahmat, K. Das, and P. Hubert, “Interaction stresses in carbon nanotube-polymer nanocomposites,” ACS Applied Materials & Interfaces, vol. 3, no. 9, pp. 3425–3431, 2011.
View at: Publisher Site | Google Scholar
W. A. Chapkin, D. Q. McNerny, M. F. Aldridge et al., “Real-time assessment of carbon nanotube alignment in a polymer matrix under an applied electric field via polarized Raman spectroscopy,” Polymer Testing, vol. 56, pp. 29–35, 2016.
View at: Publisher Site | Google Scholar
M. Baibarac, I. Baltog, and S. Lefrant, “Raman spectroscopic evidence for interfacial interactions in poly(bithiophene)/single-walled carbon nanotube composites,” Carbon, vol. 47, no. 5, pp. 1389–1398, 2009.
View at: Publisher Site | Google Scholar
X. Chen, L. Zhang, M. Zheng, C. Park, X. Wang, and C. Ke, “Quantitative nanomechanical characterization of the van der Waals interfaces between carbon nanotubes and epoxy,” Carbon, vol. 82, pp. 214–228, 2015.
View at: Publisher Site | Google Scholar
M. Rahmat and P. Hubert, “Interaction stress measurement using atomic force microscopy: a stepwise discretization method,” Journal of Physical Chemistry C, vol. 114, no. 35, pp. 15029–15035, 2010.
View at: Publisher Site | Google Scholar
M. Nie, D. M. Kalyon, K. Pochiraju, and F. T. Fisher, “A controllable way to measure the interfacial strength between carbon nanotube and polymer using a nanobridge structure,” Carbon, vol. 116, pp. 510–517, 2017.
View at: Publisher Site | Google Scholar
D. Wang and T. P. Russell, “Advances in atomic force microscopy for probing polymer structure and properties,” Macromolecules, vol. 51, no. 1, pp. 3–24, 2018.
View at: Publisher Site | Google Scholar
A. H. Barber, S. R. Cohen, and H. D. Wagner, “Measurement of carbon nanotube-polymer interfacial strength,” Applied Physics Letters, vol. 82, no. 23, pp. 4140–4142, 2003.
View at: Publisher Site | Google Scholar
M. C. Strus, C. I. Cano, R. Byron Pipes, C. V. Nguyen, and A. Raman, “Interfacial energy between carbon nanotubes and polymers measured from nanoscale peel tests in the atomic force microscope,” Composites Science and Technology, vol. 69, no. 10, pp. 1580–1586, 2009.
View at: Publisher Site | Google Scholar
A. H. Barber, S. R. Cohen, S. Kenig, and H. D. Wagner, “Interfacial fracture energy measurements for multi-walled carbon nanotubes pulled from a polymer matrix,” Composites Science and Technology, vol. 64, no. 15, pp. 2283–2289, 2004.
View at: Publisher Site | Google Scholar
A. H. Barber, S. R. Cohen, A. Eitan, L. S. Schadler, and H. D. Wagner, “Fracture transitions at a carbon-nanotube/polymer interface,” Advanced Materials, vol. 18, no. 1, pp. 83–87, 2006.
View at: Publisher Site | Google Scholar
W. Ding, A. Eitan, F. T. Fisher et al., “Direct observation of polymer sheathing in carbon nanotube-polycarbonate composites,” Nano Letters, vol. 3, no. 11, pp. 1593–1597, 2003.
View at: Publisher Site | Google Scholar
Y. Ganesan, C. Peng, Y. Lu et al., “Interface toughness of carbon nanotube reinforced epoxy composites,” ACS Applied Materials & Interfaces, vol. 3, no. 2, pp. 129–134, 2011.
View at: Publisher Site | Google Scholar
M. P. Manoharan, A. Sharma, A. V. Desai, M. A. Haque, C. E. Bakis, and K. W. Wang, “The interfacial strength of carbon nanofiber epoxy composite using single fiber pullout experiments,” Nanotechnology, vol. 20, no. 29, Article ID 295701, 2009.
View at: Publisher Site | Google Scholar
T. Tsuda, T. Ogasawara, F. Deng, and N. Takeda, “Direct measurements of interfacial shear strength of multi-walled carbon nanotube/PEEK composite using a nano-pullout method,” Composites Science and Technology, vol. 71, no. 10, pp. 1295–1300, 2011.
View at: Publisher Site | Google Scholar
S.-Y. Fu, Z.-K. Chen, S. Hong, and C. C. Han, “The reduction of carbon nanotube (CNT) length during the manufacture of CNT/polymer composites and a method to simultaneously determine the resulting CNT and interfacial strengths,” Carbon, vol. 47, no. 14, pp. 3192–3200, 2009.
View at: Publisher Site | Google Scholar
Y.-N. Liu, M. Li, Y. Gu et al., “The interfacial strength and fracture characteristics of ethanol and polymer modified carbon nanotube fibers in their epoxy composites,” Carbon, vol. 52, pp. 550–558, 2013.
View at: Publisher Site | Google Scholar
M. A. Poggi, L. A. Bottomley, and P. T. Lillehei, “Measuring the adhesion forces between alkanethiol-modified AFM cantilevers and single walled carbon nanotubes,” Nano Letters, vol. 4, no. 1, pp. 61–64, 2004.
View at: Publisher Site | Google Scholar
M. A. Poggi, P. T. Lillehei, and L. A. Bottomley, “Chemical force microscopy on single-walled carbon nanotube paper,” Chemistry of Materials, vol. 17, no. 17, pp. 4289–4295, 2005.
View at: Publisher Site | Google Scholar
I. Y. Phang, T. Liu, W.-D. Zhang, H. Schönherr, and G. J. Vancso, “Probing buried carbon nanotubes within polymer-nanotube composite matrices by atomic force microscopy,” European Polymer Journal, vol. 43, no. 10, pp. 4136–4142, 2007.
View at: Publisher Site | Google Scholar
H. T. Thompson, F. Barroso-Bujans, J. G. Herrero, R. Reifenberger, and A. Raman, “Subsurface imaging of carbon nanotube networks in polymers with DC-biased multifrequency dynamic atomic force microscopy,” Nanotechnology, vol. 24, no. 13, Article ID 135701, 2013.
View at: Publisher Site | Google Scholar
W. Wang, P. Ciselli, E. Kuznetsov, T. Peijs, and A. H. Barber, “Effective reinforcement in carbon nanotube-polymer composites,” Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol. 366, no. 1870, pp. 1613–1626, 2008.
View at: Publisher Site | Google Scholar
M. Rahmat, H. Ghiasi, and P. Hubert, “An interaction stress analysis of nanoscale elastic asperity contacts,” Nanoscale, vol. 4, no. 1, pp. 157–166, 2012.
View at: Publisher Site | Google Scholar
S. Lefrant, M. Baibarac, and I. Baltog, “Raman and FTIR spectroscopy as valuable tools for the characterization of polymer and carbon nanotube based composites,” Journal of Materials Chemistry, vol. 19, no. 32, pp. 5690–5704, 2009.
View at: Publisher Site | Google Scholar
M. Mu, S. Osswald, Y. Gogotsi, and K. I. Winey, “An in situ Raman spectroscopy study of stress transfer between carbon nanotubes and polymer,” Nanotechnology, vol. 20, no. 33, Article ID 335703, 2009.
View at: Publisher Site | Google Scholar
A. Rasheed, H. G. Chae, S. Kumar, and M. D. Dadmun, “Polymer nanotube nanocomposites: correlating intermolecular interaction to ultimate properties,” Polymer, vol. 47, no. 13, pp. 4734–4741, 2006.
View at: Publisher Site | Google Scholar
T. E. Chang, L. R. Jensen, A. Kisliuk, R. B. Pipes, R. Pyrz, and A. P. Sokolov, “Microscopic mechanism of reinforcement in single-wall carbon nanotube/polypropylene nanocomposite,” Polymer, vol. 46, no. 2, pp. 439–444, 2005.
View at: Publisher Site | Google Scholar
A. de la Vega, I. A. Kinloch, R. J. Young, W. Bauhofer, and K. Schulte, “Simultaneous global and local strain sensing in SWCNT-epoxy composites by Raman and impedance spectroscopy,” Composites Science and Technology, vol. 71, no. 2, pp. 160–166, 2011.
View at: Publisher Site | Google Scholar
L. Bokobza, J.-L. Bruneel, and M. Couzi, “Raman spectroscopic investigation of carbon-based materials and their composites. Comparison between carbon nanotubes and carbon black,” Chemical Physics Letters, vol. 590, pp. 153–159, 2013.
View at: Publisher Site | Google Scholar
L. Bokobza, J.-L. Bruneel, and M. Couzi, “Raman spectroscopy as a tool for the analysis of carbon-based materials (highly oriented pyrolitic graphite, multilayer graphene and multiwall carbon nanotubes) and of some of their elastomeric composites,” Vibrational Spectroscopy, vol. 74, pp. 57–63, 2014.
View at: Publisher Site | Google Scholar
A. Y. Glamazda, A. M. Plokhotnichenko, V. S. Leontiev, and V. A. Karachevtsev, “DNA-wrapped carbon nanotubes aligned in stretched gelatin films: polarized resonance Raman and absorption spectroscopy study,” Physica E: Low-dimensional Systems and Nanostructures, vol. 93, pp. 92–96, 2017.
View at: Publisher Site | Google Scholar
D. Roy, S. Bhattacharyya, A. Rachamim, A. Plati, and M.-L. Saboungi, “Measurement of interfacial shear strength in single wall carbon nanotubes reinforced composite using Raman spectroscopy,” Journal of Applied Physics, vol. 107, no. 4, Article ID 043501, 2010.
View at: Publisher Site | Google Scholar
N. Lachman, C. Bartholome, P. Miaudet, M. Maugey, P. Poulin, and H. D. Wagner, “Raman response of carbon nanotube/PVA fibers under strain,” Journal of Physical Chemistry C, vol. 113, no. 12, pp. 4751–4754, 2009.
View at: Publisher Site | Google Scholar
X. Yan, H. Sato, and Y. Ozaki, “Raman and tip-enhanced Raman scattering spectroscopy studies of polymer nanocomposites,” in Spectroscopy of Polymer Nanocomposites, S. Thomas, D. Rouxel, and D. Ponnamma, Eds., pp. 88–111, William Andrew Publishing, Kidlington, Oxford, UK, 2016.
View at: Publisher Site | Google Scholar
H. D. Wagner, “Raman spectroscopy of polymer-carbon nanotube composites,” in Polymer-Carbon Nanotube Composites: Preparation, Properties and Applications, A vol. in Woodhead Publishing Series in Composites Science and Engineering, T. McNally and P. Pötschke, Eds., pp. 400–427, Woodhead Publishing Limited., Sawston, Cambridge, UK, 2011.
View at: Publisher Site | Google Scholar
J. R. Wood and H. D. Wagner, “Single-wall carbon nanotubes as molecular pressure sensors,” Applied Physics Letters, vol. 76, no. 20, pp. 2883–2885, 2000.
View at: Publisher Site | Google Scholar
J. R. Wood, Q. Zhao, M. D. Frogley et al., “Carbon nanotubes: from molecular to macroscopic sensors,” Physical Review B, vol. 62, no. 11, pp. 7571–7575, 2000.
View at: Publisher Site | Google Scholar
J. R. Wood, M. D. Frogley, E. R. Meurs et al., “Mechanical response of carbon nanotubes under molecular and macroscopic pressures,” Journal of Physical Chemistry B, vol. 103, no. 47, pp. 10388–10392, 1999.
View at: Publisher Site | Google Scholar
J. R. Wood, Q. Zhao, and H. D. Wagner, “Orientation of carbon nanotubes in polymers and its detection by Raman spectroscopy,” Composites Part A: Applied Science and Manufacturing, vol. 32, no. 3-4, pp. 391–399, 2001.
View at: Publisher Site | Google Scholar
E. Francis, L. Zhai, H. Chan Kim et al., “Morphology correlated free volume studies of multi-walled carbon nanotube plasticized poly (vinyl chloride) nanocomposites: positronium probes and electrical properties,” Polymer, vol. 141, pp. 232–243, 2018.
View at: Publisher Site | Google Scholar
B. A. Newcomb, H. G. Chae, L. Thomson, J. Luo, J.-B. Baek, and S. Kumar, “Reinforcement efficiency of carbon nanotubes and their effect on crystal-crystal slip in poly(ether ketone)/carbon nanotube composite fibers,” Composites Science and Technology, vol. 147, pp. 116–125, 2017.
View at: Publisher Site | Google Scholar
H. Chang, J. Luo, H. C. Liu, A. A. Bakhtiary Davijani, P.-H. Wang, and S. Kumar, “Orientation and interfacial stress transfer of cellulose nanocrystal nanocomposite fibers,” Polymer, vol. 110, pp. 228–234, 2017.
View at: Publisher Site | Google Scholar
B. A. Newcomb, H. G. Chae, P. V. Gulgunje et al., “Stress transfer in polyacrylonitrile/carbon nanotube composite fibers,” Polymer, vol. 55, no. 11, pp. 2734–2743, 2014.
View at: Publisher Site | Google Scholar
J. Cheng, H. Pu, and J. Du, “A processing method with high efficiency for low density polyethylene nanofibers reinforced by aligned carbon nanotubes via nanolayer coextrusion,” Polymer, vol. 111, pp. 222–228, 2017.
View at: Publisher Site | Google Scholar
L. Liu, A. H. Barber, S. Nuriel, and H. D. Wagner, “Mechanical properties of functionalized single-walled carbon-nanotube/poly(vinyl alcohol) nanocomposites,” Advanced Functional Materials, vol. 15, no. 6, pp. 975–980, 2005.
View at: Publisher Site | Google Scholar
Q. Zhao and H. D. Wagner, “Raman spectroscopy of carbon-nanotube-based composites,” Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, vol. 362, no. 1824, pp. 2407–2424, 2004.
View at: Publisher Site | Google Scholar
R. Graupner, “Raman spectroscopy of covalently functionalized single-wall carbon nanotubes,” Journal of Raman Spectroscopy, vol. 38, no. 6, pp. 673–683, 2007.
View at: Publisher Site | Google Scholar
S. L. Ruan, P. Gao, X. G. Yang, and T. X. Yu, “Toughening high performance ultrahigh molecular weight polyethylene using multiwalled carbon nanotubes,” Polymer, vol. 44, no. 19, pp. 5643–5654, 2003.
View at: Publisher Site | Google Scholar
S. Ruan, P. Gao, and T. X. Yu, “Ultra-strong gel-spun UHMWPE fibers reinforced using multiwalled carbon nanotubes,” Polymer, vol. 47, no. 5, pp. 1604–1611, 2006.
View at: Publisher Site | Google Scholar
D. Puglia, L. Valentini, I. Armentano, and J. M. Kenny, “Effects of single-walled carbon nanotube incorporation on the cure reaction of epoxy resin and its detection by Raman spectroscopy,” Diamond and Related Materials, vol. 12, no. 3–7, pp. 827–832, 2003.
View at: Publisher Site | Google Scholar
M. Rahmat and P. Hubert, “Carbon nanotube-polymer interactions in nanocomposites: a review,” Composites Science and Technology, vol. 72, no. 1, pp. 72–84, 2011.
View at: Publisher Site | Google Scholar
N. Ning, D. Cheng, J. Yang et al., “New insight on the interfacial interaction between multiwalled carbon nanotubes and elastomers,” Composites Science and Technology, vol. 142, pp. 214–220, 2017.
View at: Publisher Site | Google Scholar
H. Li, S. Liu, P. Li et al., “Interfacial control and carrier tuning of carbon nanotube/polyaniline composites for high thermoelectric performance,” Carbon, vol. 136, pp. 292–298, 2018.
View at: Publisher Site | Google Scholar
X. Yao, X. Gao, J. Jiang, C. Xu, C. Deng, and J. Wang, “Comparison of carbon nanotubes and graphene oxide coated carbon fiber for improving the interfacial properties of carbon fiber/epoxy composites,” Composites Part B: Engineering, vol. 132, pp. 170–177, 2018.
View at: Publisher Site | Google Scholar
T. Palacin, H. L. Khanh, B. Jousselme et al., “Efficient functionalization of carbon nanotubes with porphyrin dendrons via click chemistry,” Journal of the American Chemical Society, vol. 131, no. 42, pp. 15394–15402, 2009.
View at: Publisher Site | Google Scholar
M. Rafiee, F. Nitzsche, and M. R. Labrosse, “Effect of functionalization of carbon nanotubes on vibration and damping characteristics of epoxy nanocomposites,” Polymer Testing, vol. 69, pp. 385–395, 2018.
View at: Publisher Site | Google Scholar
S. H. Boroushak, R. Ansari, and S. Ajori, “Molecular dynamics simulations of the thermal conductivity of cross-linked functionalized single- and double-walled carbon nanotubes with polyethylene chains,” Diamond and Related Materials, vol. 86, pp. 173–178, 2018.
View at: Publisher Site | Google Scholar
G. Zamfirova, V. Gaydarov, F. Faraguna, E. Vidović, and A. Jukić, “Influence of carbon nanotubes functionalization on the mechanical properties of polymethacrylate nanocomposites,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 510, pp. 169–175, 2016.
View at: Publisher Site | Google Scholar
J. Gao, M. A. Loi, E. J. F. de Carvalho, and M. C. dos Santos, “Selective wrapping and supramolecular structures of polyfluorene-carbon nanotube hybrids,” ACS Nano, vol. 5, no. 5, pp. 3993–3999, 2011.
View at: Publisher Site | Google Scholar
L. Wang, Y. Tan, X. Wang, T. Xu, C. Xiao, and Z. Qi, “Mechanical and fracture properties of hyperbranched polymer covalent functionalized multiwalled carbon nanotube-reinforced epoxy composites,” Chemical Physics Letters, vol. 706, pp. 31–39, 2018.
View at: Publisher Site | Google Scholar
C. Min, D. Liu, Z. He, S. Li, K. Zhang, and Y. Huang, “Preparation of novel polyimide nanocomposites with high mechanical and tribological performance using covalent modified carbon nanotubes via Friedel-Crafts reaction,” Polymer, vol. 150, pp. 223–231, 2018.
View at: Publisher Site | Google Scholar
T. Tsafack, J. M. Alred, K. E. Wise, B. Jensen, E. Siochi, and B. I. Yakobson, “Exploring the interface between single-walled carbon nanotubes and epoxy resin,” Carbon, vol. 105, pp. 600–606, 2016.
View at: Publisher Site | Google Scholar
A. A. B. Davijani, H. Chang, H. C. Liu, J. Luo, and S. Kumar, “Stress transfer in nanocomposites enabled by poly(methyl methacrylate) wrapping of carbon nanotubes,” Polymer, vol. 130, pp. 191–198, 2017.
View at: Publisher Site | Google Scholar
Y.-Q. Huang, Y.-Y. Zhong, R. Zhang et al., “Tuning the backbones and side chains of cationic meta-linked poly(phenylene ethynylene)s: different conformational modes, tunable light emission, and helical wrapping of multi-walled carbon nanotubes,” Polymer, vol. 102, pp. 143–152, 2016.
View at: Publisher Site | Google Scholar
Y. Li, D. Yang, A. Adronov, Y. Gao, X. Luo, and H. Li, “Covalent functionalization of single-walled carbon nanotubes with thermoresponsive core cross-linked polymeric micelles,” Macromolecules, vol. 45, no. 11, pp. 4698–4706, 2012.
View at: Publisher Site | Google Scholar
K. M. Lee, L. Li, and L. Dai, “Asymmetric end-functionalization of multi-walled carbon nanotubes,” Journal of the American Chemical Society, vol. 127, no. 12, pp. 4122-4123, 2005.
View at: Publisher Site | Google Scholar
C. Bergeret, J. Cousseau, V. Fernandez, J.-Y. Mevellec, and S. Lefrant, “Spectroscopic evidence of carbon nanotubes’ metallic character loss induced by covalent functionalization via nitric acid purification,” Journal of Physical Chemistry C, vol. 112, no. 42, pp. 16411–16416, 2008.
View at: Publisher Site | Google Scholar
K. S. Lee, M. Park, J. M. Ko, and J.-D. Kim, “Electrochemical properties of multi-walled carbon nanotubes treated with nitric acid for a supercapacitor electrode,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 506, pp. 664–669, 2016.
View at: Publisher Site | Google Scholar
J. Ramirez, M. L. Mayo, S. Kilina, and S. Tretiak, “Electronic structure and optical spectra of semiconducting carbon nanotubes functionalized by diazonium salts,” Chemical Physics, vol. 413, pp. 89–101, 2013.
View at: Publisher Site | Google Scholar
C. M. Q. Le, X. T. Cao, Y. T. Jeong, and K. T. Lim, “Covalent functionalization of multi-walled carbon nanotubes with imidazolium-based poly(ionic liquid)s by Diels-Alder “click” reaction,” Journal of Industrial and Engineering Chemistry, vol. 64, pp. 337–343, 2018.
View at: Publisher Site | Google Scholar
K. Mosnáčková, J. Kollár, Y.-S. Huang, C.-F. Huang, and J. Mosnáček, “Synthesis routes of functionalized nanoparticles,” in Polymer Composites with Functional Nanoparticles: Synthesis, Properties, and Applications, A vol. in Micro and Nano Technologies, K. Pielichowski and T. M. Majka, Eds., Elsevier Ltd., Amsterdam, Netherlands, 2019.
View at: Publisher Site | Google Scholar
C. Wei, B. Akinwolemiwa, L. Yu, D. Hu, and G. Z. Chen, “Polymer composites with functionalized carbon nanotube and graphene,” in Polymer Composites with Functional Nanoparticles: Synthesis, Properties, and Applications, A vol. in Micro and Nano Technologies, K. Pielichowski and T. M. Majka, Eds., Elsevier Ltd., Amsterdam, Netherlands, 2019.
View at: Publisher Site | Google Scholar
F. H. Gojny and K. Schulte, “Functionalisation effect on the thermo-mechanical behaviour of multi-wall carbon nanotube/epoxy-composites,” Composites Science and Technology, vol. 64, no. 15, pp. 2303–2308, 2004.
View at: Publisher Site | Google Scholar
F. H. Gojny, J. Nastalczyk, Z. Roslaniec, and K. Schulte, “Surface modified multi-walled carbon nanotubes in CNT/epoxy-composites,” Chemical Physics Letters, vol. 370, no. 5-6, pp. 820–824, 2003.
View at: Publisher Site | Google Scholar
B. Ruelle, S. Peeterbroeck, C. Bittencourt et al., “Semi-crystalline polymer/carbon nanotube nanocomposites: effect of nanotube surface-functionalization and polymer coating on electrical and thermal properties,” Reactive and Functional Polymers, vol. 72, no. 6, pp. 383–392, 2012.
View at: Publisher Site | Google Scholar
Y. J. Kim, T. S. Shin, H. D. Choi, J. H. Kwon, Y.-C. Chung, and H. G. Yoon, “Electrical conductivity of chemically modified multiwalled carbon nanotube/epoxy composites,” Carbon, vol. 43, no. 1, pp. 23–30, 2005.
View at: Publisher Site | Google Scholar
A. A. B. Davijani and S. Kumar, “Ordered wrapping of poly(methyl methacrylate) on single wall carbon nanotubes,” Polymer, vol. 70, pp. 278–281, 2015.
View at: Publisher Site | Google Scholar
A. Nish, J.-Y. Hwang, J. Doig, and R. J. Nicholas, “Highly selective dispersion of single-walled carbon nanotubes using aromatic polymers,” Nature Nanotechnology, vol. 2, no. 10, pp. 640–646, 2007.
View at: Publisher Site | Google Scholar
X. Tu, S. Manohar, A. Jagota, and M. Zheng, “DNA sequence motifs for structure-specific recognition and separation of carbon nanotubes,” Nature, vol. 460, no. 7252, pp. 250–253, 2009.
View at: Publisher Site | Google Scholar
M. J. O’Connell, P. Boul, L. M. Ericson et al., “Reversible water-solubilization of single-walled carbon nanotubes by polymer wrapping,” Chemical Physics Letters, vol. 342, no. 3-4, pp. 265–271, 2001.
View at: Publisher Site | Google Scholar
S. K. Samanta, M. Fritsch, U. Scherf, W. Gomulya, S. Z. Bisri, and M. A. Loi, “Conjugated polymer-assisted dispersion of single-wall carbon nanotubes: the power of polymer wrapping,” Accounts of Chemical Research, vol. 47, no. 8, pp. 2446–2456, 2014.
View at: Publisher Site | Google Scholar
T. Lei, I. Pochorovski, and Z. Bao, “Separation of semiconducting carbon nanotubes for flexible and stretchable electronics using polymer removable method,” Accounts of Chemical Research, vol. 50, no. 4, pp. 1096–1104, 2017.
View at: Publisher Site | Google Scholar
J. Ouyang, J. Ding, J. Lefebvre et al., “Sorting of semiconducting single-walled carbon nanotubes in polar solvents with an amphiphilic conjugated polymer provides general guidelines for enrichment,” ACS Nano, vol. 12, no. 2, pp. 1910–1919, 2018.
View at: Publisher Site | Google Scholar
P. Deria, C. D. Von Bargen, J.-H. Olivier, A. S. Kumbhar, J. G. Saven, and M. J. Therien, “Single-handed helical wrapping of single-walled carbon nanotubes by chiral, ionic, semiconducting polymers,” Journal of the American Chemical Society, vol. 135, no. 43, pp. 16220–16234, 2013.
View at: Publisher Site | Google Scholar
S. Badaire, C. Zakri, M. Maugey et al., “Liquid crystals of DNA-stabilized carbon nanotubes,” Advanced Materials, vol. 17, no. 13, pp. 1673–1676, 2005.
View at: Publisher Site | Google Scholar
P. V. Jena, M. M. Safaee, D. A. Heller, and D. Roxbury, “DNA-carbon nanotube complexation affinity and photoluminescence modulation are independent,” ACS Applied Materials & Interfaces, vol. 9, no. 25, pp. 21397–21405, 2017.
View at: Publisher Site | Google Scholar
R. Shvartzman-Cohen, Y. Levi-Kalisman, E. Nativ-Roth, and R. Yerushalmi-Rozen, “Generic approach for dispersing single-walled carbon nanotubes: the strength of a weak interaction,” Langmuir, vol. 20, no. 15, pp. 6085–6088, 2004.
View at: Publisher Site | Google Scholar
H. S. Park, B. G. Choi, W. H. Hong, and S.-Y. Jang, “Interfacial interactions of single-walled carbon nanotube/conjugated block copolymer hybrids for flexible transparent conductive films,” Journal of Physical Chemistry C, vol. 116, no. 14, pp. 7962–7967, 2012.
View at: Publisher Site | Google Scholar
N. A. Rice, A. V. Subrahmanyam, B. R. Coleman, and A. Adronov, “Effect of induction on the dispersion of semiconducting and metallic single-walled carbon nanotubes using conjugated polymers,” Macromolecules, vol. 48, no. 15, pp. 5155–5161, 2015.
View at: Publisher Site | Google Scholar
T. Lei, X. Chen, G. Pitner, H.-S. P. Wong, and Z. Bao, “Removable and recyclable conjugated polymers for highly selective and high-yield dispersion and release of low-cost carbon nanotubes,” Journal of the American Chemical Society, vol. 138, no. 3, pp. 802–805, 2016.
View at: Publisher Site | Google Scholar
W. Chung, K. Nobusawa, H. Kamikubo, M. Kataoka, M. Fujiki, and M. Naito, “Time-resolved observation of chiral-index-selective wrapping on single-walled carbon nanotube with non-aromatic polysilane,” Journal of the American Chemical Society, vol. 135, no. 6, pp. 2374–2383, 2013.
View at: Publisher Site | Google Scholar
M. Yang, V. Koutsos, and M. Zaiser, “Interactions between polymers and carbon nanotubes: a molecular dynamics study,” Journal of Physical Chemistry B, vol. 109, no. 20, pp. 10009–10014, 2005.
View at: Publisher Site | Google Scholar
S. S. Tallury and M. A. Pasquinelli, “Molecular dynamics simulations of polymers with stiff backbones interacting with single-walled carbon nanotubes,” Journal of Physical Chemistry B, vol. 114, no. 29, pp. 9349–9355, 2010.
View at: Publisher Site | Google Scholar
S. S. Tallury and M. A. Pasquinelli, “Molecular dynamics simulations of flexible polymer chains wrapping single-walled carbon nanotubes,” Journal of Physical Chemistry B, vol. 114, no. 12, pp. 4122–4129, 2010.
View at: Publisher Site | Google Scholar
J. Gou, B. Minaie, B. Wang, Z. Liang, and C. Zhang, “Computational and experimental study of interfacial bonding of single-walled nanotube reinforced composites,” Computational Materials Science, vol. 31, no. 3-4, pp. 225–236, 2004.
View at: Publisher Site | Google Scholar
I. Kusner and S. Srebnik, “Conformational behavior of semi-flexible polymers confined to a cylindrical surface,” Chemical Physics Letters, vol. 430, no. 1–3, pp. 84–88, 2006.
View at: Publisher Site | Google Scholar
J. Chen, H. Liu, W. A. Weimer, M. D. Halls, D. H. Waldeck, and G. C. Walker, “Noncovalent engineering of carbon nanotube surfaces by rigid, functional conjugated polymers,” Journal of the American Chemical Society, vol. 124, no. 31, pp. 9034-9035, 2002.
View at: Publisher Site | Google Scholar
P. Kelich and A. Asadinezhad, “Molecular dynamics insights into behavior of poly(ethylene succinate) single chain on carbon nanotube surface,” Journal of Physical Chemistry C, vol. 119, no. 46, pp. 26143–26153, 2015.
View at: Publisher Site | Google Scholar
Z. Qi, Y. Tan, H. Wang, T. Xu, L. Wang, and C. Xiao, “Effects of noncovalently functionalized multiwalled carbon nanotube with hyperbranched polyesters on mechanical properties of epoxy composites,” Polymer Testing, vol. 64, pp. 38–47, 2017.
View at: Publisher Site | Google Scholar
A. Mandal and A. K. Nandi, “Noncovalent functionalization of multiwalled carbon nanotube by a polythiophene-based compatibilizer: reinforcement and conductivity improvement in poly(vinylidene fluoride) films,” Journal of Physical Chemistry C, vol. 116, no. 16, pp. 9360–9371, 2012.
View at: Publisher Site | Google Scholar
W. Yuan, W. Li, Y. Mu, and M. B. Chan-Park, “Effect of side-chain structure of rigid polyimide dispersant on mechanical properties of single-walled carbon nanotube/cyanate ester composite,” ACS Applied Materials & Interfaces, vol. 3, no. 5, pp. 1702–1712, 2011.
View at: Publisher Site | Google Scholar
W. Yuan, J. Feng, Z. Judeh, J. Dai, and M. B. Chan-Park, “Use of polyimide-graft-bisphenol a diglyceryl acrylate as a reactive noncovalent dispersant of single-walled carbon nanotubes for reinforcement of cyanate ester/epoxy composite,” Chemistry of Materials, vol. 22, no. 24, pp. 6542–6554, 2010.
View at: Publisher Site | Google Scholar
J. Cha, S. Jin, J. H. Shim, C. S. Park, H. J. Ryu, and S. H. Hong, “Functionalization of carbon nanotubes for fabrication of CNT/epoxy nanocomposites,” Materials & Design, vol. 95, pp. 1–8, 2016.
View at: Publisher Site | Google Scholar
E. Y. Choi, S. C. Roh, and C. K. Kim, “Noncovalent functionalization of multi-walled carbon nanotubes with pyrene-linked nylon66 for high performance nylon66/multi-walled carbon nanotube composites,” Carbon, vol. 72, pp. 160–168, 2014.
View at: Publisher Site | Google Scholar
J. M. Gonzalez-Dominguez, M. A. Tesa-Serrate, A. Anson-Casaos, A. M. Diez-Pascual, M. A. Gomez-Fatou, and M. T. Martinez, “Wrapping of SWCNTs in polyethylenoxide-based amphiphilic diblock copolymers: an approach to purification, debundling, and integration into the epoxy matrix,” Journal of Physical Chemistry C, vol. 116, no. 13, pp. 7399–7408, 2012.
View at: Publisher Site | Google Scholar
N. E. Kallmyer, T. Huynh, J. C. Graves, J. Musielewicz, D. Tamiev, and N. F. Reuel, “Influence of sonication conditions and wrapping type on yield and fluorescent quality of noncovalently functionalized single-walled carbon nanotubes,” Carbon, vol. 139, pp. 609–613, 2018.
View at: Publisher Site | Google Scholar
Q. L. Xiong and S. A. Meguid, “Atomistic investigation of the interfacial mechanical characteristics of carbon nanotube reinforced epoxy composite,” European Polymer Journal, vol. 69, pp. 1–15, 2015.
View at: Publisher Site | Google Scholar
J. Chen, X. Cui, Y. Zhu, W. Jiang, and K. Sui, “Design of superior conductive polymer composite with precisely controlling carbon nanotubes at the interface of a co-continuous polymer blend via a balance of π-π interactions and dipole-dipole interactions,” Carbon, vol. 114, pp. 441–448, 2017.
View at: Publisher Site | Google Scholar
M. Wong, M. Paramsothy, X. J. Xu, Y. Ren, S. Li, and K. Liao, “Physical interactions at carbon nanotube-polymer interface,” Polymer, vol. 44, no. 25, pp. 7757–7764, 2003.
View at: Publisher Site | Google Scholar
J. M. Wernik, B. J. Cornwell-Mott, and S. A. Meguid, “Determination of the interfacial properties of carbon nanotube reinforced polymer composites using atomistic-based continuum model,” International Journal of Solids and Structures, vol. 49, no. 13, pp. 1852–1863, 2012.
View at: Publisher Site | Google Scholar
G. Zhu, X. Wang, Y. Jiang, and J. Zheng, “In situ construction of dual-noncovalent bonding to prepare enhanced carbon nanotubes/poly(methyl methacrylate) nanocomposites,” Composites Science and Technology, vol. 155, pp. 58–63, 2018.
View at: Publisher Site | Google Scholar
R. K. Prusty, D. K. Rathore, and B. C. Ray, “CNT/polymer interface in polymeric composites and its sensitivity study at different environments,” Advances in Colloid and Interface Science, vol. 240, pp. 77–106, 2017.
View at: Publisher Site | Google Scholar
R. Nadiv, R. M. F. Fernandes, G. Ochbaum et al., “Polymer nanocomposites: insights on rheology, percolation and molecular mobility,” Polymer, vol. 153, pp. 52–60, 2018.
View at: Publisher Site | Google Scholar
C. Ma, H.-Y. Liu, X. Du, L. Mach, F. Xu, and Y.-W. Mai, “Fracture resistance, thermal and electrical properties of epoxy composites containing aligned carbon nanotubes by low magnetic field,” Composites Science and Technology, vol. 114, pp. 126–135, 2015.
View at: Publisher Site | Google Scholar
C. Bower, R. Rosen, L. Jin, J. Han, and O. Zhou, “Deformation of carbon nanotubes in nanotube-polymer composites,” Applied Physics Letters, vol. 74, no. 22, pp. 3317–3319, 1999.
View at: Publisher Site | Google Scholar
M. Shtein, R. Nadiv, N. Lachman, H. Daniel Wagner, and O. Regev, “Fracture behavior of nanotube-polymer composites: insights on surface roughness and failure mechanism,” Composites Science and Technology, vol. 87, pp. 157–163, 2013.
View at: Publisher Site | Google Scholar
D. Qian, E. C. Dickey, R. Andrews, and T. Rantell, “Load transfer and deformation mechanisms in carbon nanotube-polystyrene composites,” Applied Physics Letters, vol. 76, no. 20, pp. 2868–2870, 2000.
View at: Publisher Site | Google Scholar
G. G. Tibbetts and J. J. McHugh, “Mechanical properties of vapor-grown carbon fiber composites with thermoplastic matrices,” Journal of Materials Research, vol. 14, no. 7, pp. 2871–2880, 1999.
View at: Publisher Site | Google Scholar
J. Gupta, C. Wan, D. M. Haddleton, and T. McNally, “Plasticisation and compatibilisation of poly(propylene) with poly(lauryl acrylate) surface modified MWCNTs,” Polymer, vol. 133, pp. 89–101, 2017.
View at: Publisher Site | Google Scholar
D. Roy, N. Tiwari, K. Mukhopadhyay, and A. K. Saxena, “The effect of a doubly modified carbon nanotube derivative on the microstructure of epoxy resin,” Polymer, vol. 55, no. 2, pp. 583–593, 2014.
View at: Publisher Site | Google Scholar
S. Mallakpour and A. N. Ezhieh, “Preparation and characterization of chitosan-poly(vinyl alcohol) nanocomposite films embedded with functionalized multi-walled carbon nanotube,” Carbohydrate Polymers, vol. 166, pp. 377–386, 2017.
View at: Publisher Site | Google Scholar
K. C. Jajam, M. M. Rahman, M. V. Hosur, and H. V. Tippur, “Fracture behavior of epoxy nanocomposites modified with polyol diluent and amino-functionalized multi-walled carbon nanotubes: a loading rate study,” Composites Part A: Applied Science and Manufacturing, vol. 59, pp. 57–69, 2014.
View at: Publisher Site | Google Scholar
A. Kis and A. Zettl, “Nanomechanics of carbon nanotubes,” Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol. 366, no. 1870, pp. 1591–1611, 2008.
View at: Publisher Site | Google Scholar
A. O. Monteiro, P. B. Cachim, and P. M. F. J. Costa, “Mechanics of filled carbon nanotubes,” Diamond and Related Materials, vol. 44, pp. 11–25, 2014.
View at: Publisher Site | Google Scholar
N. Karousis, N. Tagmatarchis, and D. Tasis, “Current progress on the chemical modification of carbon nanotubes,” Chemical Reviews, vol. 110, no. 9, pp. 5366–5397, 2010.
View at: Publisher Site | Google Scholar
Y.-P. Sun, K. Fu, Y. Lin, and W. Huang, “Functionalized carbon nanotubes: properties and applications,” Accounts of Chemical Research, vol. 35, no. 12, pp. 1096–1104, 2002.
View at: Publisher Site | Google Scholar
T. Wang, X. Hu, X. Qu, and S. Dong, “Noncovalent functionalization of multiwalled carbon nanotubes: application in hybrid nanostructures,” Journal of Physical Chemistry B, vol. 110, no. 13, pp. 6631–6636, 2006.
View at: Publisher Site | Google Scholar
Y.-L. Zhao and J. F. Stoddart, “Noncovalent functionalization of single-walled carbon nanotubes,” Accounts of Chemical Research, vol. 42, no. 8, pp. 1161–1171, 2009.
View at: Publisher Site | Google Scholar
P. S. Omurtag, B. Alkan, H. Durmaz, G. Hizal, and U. Tunca, “Indirect functionalization of multiwalled carbon nano tubes through non-covalent interaction of functional polyesters,” Polymer, vol. 141, pp. 213–220, 2018.
View at: Publisher Site | Google Scholar
C.-C. Yang, Y.-C. Lin, P.-I. Wang, D.-J. Liaw, and S.-W. Kuo, “Polybenzoxazine/single-walled carbon nanotube nanocomposites stabilized through noncovalent bonding interactions,” Polymer, vol. 55, no. 8, pp. 2044–2050, 2014.
View at: Publisher Site | Google Scholar
S. Shenogin, L. Xue, R. Ozisik, P. Keblinski, and D. G. Cahill, “Role of thermal boundary resistance on the heat flow in carbon-nanotube composites,” Journal of Applied Physics, vol. 95, no. 12, pp. 8136–8144, 2004.
View at: Publisher Site | Google Scholar
S. T. Huxtable, D. G. Cahill, S. Shenogin et al., “Interfacial heat flow in carbon nanotube suspensions,” Nature Materials, vol. 2, no. 11, pp. 731–734, 2003.
View at: Publisher Site | Google Scholar
S. Shenogin, A. Bodapati, L. Xue, R. Ozisik, and P. Keblinski, “Effect of chemical functionalization on thermal transport of carbon nanotube composites,” Applied Physics Letters, vol. 85, no. 12, pp. 2229–2231, 2004.
View at: Publisher Site | Google Scholar
T. C. Clancy and T. S. Gates, “Modeling of interfacial modification effects on thermal conductivity of carbon nanotube composites,” Polymer, vol. 47, no. 16, pp. 5990–5996, 2006.
View at: Publisher Site | Google Scholar
M. B. Bryning, D. E. Milkie, M. F. Islam, J. M. Kikkawa, and A. G. Yodh, “Thermal conductivity and interfacial resistance in single-wall carbon nanotube epoxy composites,” Applied Physics Letters, vol. 87, no. 16, Article ID 161909, 2005.
View at: Publisher Site | Google Scholar
V. Varshney, A. K. Roy, T. J. Michalak, J. Lee, and B. L. Farmer, “Effect of curing and functionalization on the interface thermal conductance in carbon nanotube-epoxy composites,” JOM, vol. 65, no. 2, pp. 140–146, 2013.
View at: Publisher Site | Google Scholar
L. Gao, X. Zhou, and Y. Ding, “Effective thermal and electrical conductivity of carbon nanotube composites,” Chemical Physics Letters, vol. 434, no. 4–6, pp. 297–300, 2007.
View at: Publisher Site | Google Scholar
N. A. Fasanella and V. Sundararaghavan, “Atomistic modeling of thermal conductivity of epoxy nanotube composites,” JOM, vol. 68, no. 5, pp. 1396–1410, 2016.
View at: Publisher Site | Google Scholar
H. Huang, L. Chen, V. Varshney, A. K. Roy, and S. Kumar, “Investigation of phonon transport and thermal boundary conductance at the interface of functionalized SWCNT and poly (ether-ketone),” Journal of Applied Physics, vol. 120, no. 9, Article ID 095102, 2016.
View at: Publisher Site | Google Scholar
S. Ju and Z. Y. Li, “Theory of thermal conductance in carbon nanotube composites,” Physics Letters A, vol. 353, no. 2-3, pp. 194–197, 2006.
View at: Publisher Site | Google Scholar
Z. Xu and M. J. Buehler, “Nanoengineering heat transfer performance at carbon nanotube interfaces,” ACS Nano, vol. 3, no. 9, pp. 2767–2775, 2009.
View at: Publisher Site | Google Scholar
S. Y. Kim, H. G. Jang, C.-M. Yang, and B. J. Yang, “Multiscale prediction of thermal conductivity for nanocomposites containing crumpled carbon nanofillers with interfacial characteristics,” Composites Science and Technology, vol. 155, pp. 169–176, 2018.
View at: Publisher Site | Google Scholar
H. Zhong and J. R. Lukes, “Interfacial thermal resistance between carbon nanotubes: molecular dynamics simulations and analytical thermal modeling,” Physical Review B, vol. 74, no. 12, Article ID 125403, 2006.
View at: Publisher Site | Google Scholar
D. Estrada and E. Pop, “Imaging dissipation and hot spots in carbon nanotube network transistors,” Applied Physics Letters, vol. 98, no. 7, Article ID 073102, 2011.
View at: Publisher Site | Google Scholar
F. H. Gojny, M. H. G. Wichmann, B. Fiedler et al., “Evaluation and identification of electrical and thermal conduction mechanisms in carbon nanotube/epoxy composites,” Polymer, vol. 47, no. 6, pp. 2036–2045, 2006.
View at: Publisher Site | Google Scholar
B. Fiedler, F. H. Gojny, M. H. G. Wichmann, M. C. M. Nolte, and K. Schulte, “Fundamental aspects of nano-reinforced composites,” Composites Science and Technology, vol. 66, no. 16, pp. 3115–3125, 2006.
View at: Publisher Site | Google Scholar
S.-Y. Yang, C.-C. M. Ma, C.-C. Teng et al., “Effect of functionalized carbon nanotubes on the thermal conductivity of epoxy composites,” Carbon, vol. 48, no. 3, pp. 592–603, 2010.
View at: Publisher Site | Google Scholar
Y. Kuang and B. Huang, “Effects of covalent functionalization on the thermal transport in carbon nanotube/polymer composites: a multi-scale investigation,” Polymer, vol. 56, pp. 563–571, 2015.
View at: Publisher Site | Google Scholar
C. H. Liu and S. S. Fan, “Effects of chemical modifications on the thermal conductivity of carbon nanotube composites,” Applied Physics Letters, vol. 86, no. 12, Article ID 123106, 2005.
View at: Publisher Site | Google Scholar
C. Baudot and C. M. Tan, “Covalent functionalization of carbon nanotubes and their use in dielectric epoxy composites to improve heat dissipation,” Carbon, vol. 49, no. 7, pp. 2362–2369, 2011.
View at: Publisher Site | Google Scholar
W. Chen, J. Zhang, and Y. Yue, “Molecular dynamics study on thermal transport at carbon nanotube interface junctions: effects of mechanical force and chemical functionalization,” International Journal of Heat and Mass Transfer, vol. 103, pp. 1058–1064, 2016.
View at: Publisher Site | Google Scholar
C. Guo, F. Xin, C. Zhai, and Y. Chen, “Flammability and thermal properties of modified carbon nanotubes in poly(lactic acid),” Journal of Thermoplastic Composite Materials, vol. 27, Article ID 089270571878567, 2018, In Press.
View at: Publisher Site | Google Scholar

Copyright

Copyright © 2019 Junjie Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

PDF Download Citation

Download other formats

Order printed copies

Views

2902

Downloads

1598

Citations