Journal of Nanomaterials The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Supercritical CO2 Assisted Synthesis of EDTA-Fe3O4 Nanocomposite with High Adsorption Capacity for Hexavalent Chromium Wed, 30 Nov 2016 14:27:31 +0000 Efficiency of EDTA functionalized nanoparticles in adsorption of chromium (VI) from water was investigated in this study. Magnetic iron oxide nanoparticles (IONPs) were synthesized by a simple chemical coprecipitation route and EDTA coating onto IONPs was attained via supercritical carbon dioxide (Sc CO2), a technology with green sustainable properties. The obtained nanoparticles were then characterized by UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and vibrating magnetometric analysis (VSM). The synthesized nanoparticle and its modified variant were evaluated as adsorbent for chromium (VI) removal from water through batch adsorption technique and the effect of analytic concentration; contact time and adsorbent concentration were studied at pH 2. The results showed higher removal efficiency for modified magnetic iron oxide nanoparticles (MIONPs) (i.e., 99.9%) than their nonmodified variant IONPs, that is, 34.06% for the same concentration after 18 hours of incubation. Also maximum adsorption capacity ( = 452.26 mg/g) of MIONPs attained can be related to their preparation in Sc CO2 as calculated from IONPs, that is, 170.33 mg/g, is lower than that of MIONPs. The adsorption data fit well with Freundlich isotherm equation while kinetic adsorption studies of chromium (VI) were modeled by pseudo-second-order model. Gunjan Bisht, Sanjila Neupane, and Rebika Makaju Copyright © 2016 Gunjan Bisht et al. All rights reserved. Influence of Concentration and Electrodeposition Time on the Electrochemical Supercapacitor Performance of Poly(3,4-Ethylenedioxythiophene)/Graphene Oxide Hybrid Material Wed, 30 Nov 2016 13:24:59 +0000 Poly(3,4-ethylenedioxythiophene)/graphene oxide (PEDOT/GO) composites with wrinkled paper-like sheets morphology were electropolymerized potentiostatically at 1.2 V with different electrodeposition times (1–30 min) and various concentrations of GO (0.5, 1.0, 1.5, and 2.0 mg/mL). The electrochemical properties of PEDOT/GO composites as an electrode material for supercapacitor were investigated using cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge (GCD). The CV results revealed that PEDOT/GO containing 1.0 mg/mL GO and electropolymerized for 10 minutes exhibited the highest specific capacitance (157.17 F/g). This optimum PEDOT/GO was found to have energy and power density of 18.24 W/kg and 496.64 Wh/kg, respectively, at 1.0 A/g current density. The resistance of charge transfer obtained for PEDOT/GO is very low (13.10 Ω) compared to PEDOT (638.98 Ω), proving that PEDOT/GO has a good supercapacitive performance due to the synergistic effect of the high conductivity of PEDOT and large surface area of GO. Nur Hawa Nabilah Azman, Hong Ngee Lim, and Yusran Sulaiman Copyright © 2016 Nur Hawa Nabilah Azman et al. All rights reserved. Comparative Study of Ag Nanostructures: Molecular Simulations, Electrochemical Behavior, and Antibacterial Effect Wed, 30 Nov 2016 13:17:34 +0000 Nanoparticles of Ag with different sizes and structures were obtained and studied. Two methods for reductions of Ag ions were employed, chemical reduction by sodium borohydride and ethylene glycol. Cuboctahedral and icosahedral structures were obtained. Molecular simulations were carried out in order to evaluate the reactivity of both structures. On the other hand, the electrochemical activity and antibacterial effect (E. coli) of the cuboctahedral and icosahedral structures were measured experimentally. The results obtained by molecular simulation, cyclic voltammetry, and antibacterial effect were compared and discussed in this work. Álvaro de Jesús Ruíz-Baltazar, Simón Yobanny Reyes-López, D. Larrañaga, and R. Pérez Copyright © 2016 Álvaro de Jesús Ruíz-Baltazar et al. All rights reserved. Highly Efficient Adsorption of Aqueous Pb(II) with Mesoporous Metal-Organic Framework-5: An Equilibrium and Kinetic Study Mon, 28 Nov 2016 12:12:06 +0000 Mesoporous metal-organic framework-5 (MOF-5), with the composition Zn4O(BDC)3, showed a high capacity for the adsorptive removal of Pb(II) from 100% aqueous media. After the adsorption process, changes in both morphology and composition were detected using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) system, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis. The experimental evidence showed that Zn(II) liberation from MOF-5 structure was provoked by the water effect demonstrating that Pb(II) removal is not due to ionic exchange with Zn. A kinetic study showed that Pb(II) removal was carried out in 30 min with a behavior of pseudo-second-order kinetic model. The experimental data on Pb(II) adsorption were adequately fit by both the Langmuir and BET isotherm models with maximum adsorption capacities of 658.5 and 412.7 mg/g, respectively, at pH 5 and 45°C. The results of this work demonstrate that the use of MOF-5 has great potential for applications in environmental protection, especially regarding the removal of the lead present in industrial wastewaters and tap waters. José María Rivera, Susana Rincón, Cherif Ben Youssef, and Alejandro Zepeda Copyright © 2016 José María Rivera et al. All rights reserved. Out-of-Plane and In-Plane Magnetization Behavior of Dipolar Interacting FeNi Nanoislands around the Percolation Threshold Sun, 27 Nov 2016 08:55:17 +0000 Magnetic properties of inhomogeneous nanoisland FeNi films were studied by SQUID magnetometry. The FeNi films with nominal thickness ranging from 0.6 to 2.0 nm were deposited by rf sputtering on Sitall glass substrates and covered by a protecting Al2O3 layer on the top. The SQUID data indicate pronounced irreversibility behavior for the out-of-plane temperature-dependent magnetization response (measured at  Oe) using zero-field cooling (ZFC) and field-cooled warming (FCW) after the applied dc magnetizing field  T for the FeNi samples with nominal thickness 1.1 nm  nm, below the percolation threshold. The positive difference between the FCW and ZFC data identifies two irreversibility temperature scales,  K and  K, which can be associated with the superparamagnetic and superferromagnetic behavior in inhomogeneous nanoisland FeNi films, respectively. However, above the film percolation threshold, we observed a crossover from the out-of-plane to in-plane magnetization orientation. Here, the in-plane FCW-ZFC difference implies negative remanent magnetization response in the temperature range . The observed magnetization properties can be associated with the presence of the superferromagnetic phase in self-assembled clusters of quasi-2D metallic magnetic FeNi nanoislands. A. Stupakov, A. V. Bagdinov, V. V. Prokhorov, A. N. Bagdinova, E. I. Demikhov, A. Dejneka, K. I. Kugel, A. A. Gorbatsevich, F. A. Pudonin, and N. N. Kovaleva Copyright © 2016 A. Stupakov et al. All rights reserved. Photocatalytic Reduction Activity of Codoped with F and Fe under Visible Light for Bromate Removal Thu, 24 Nov 2016 14:28:54 +0000 The presence of bromate in water is a well-known problem because of its toxic effects on human health, particularly its carcinogenic potential. Photocatalytic reduction is an attractive process for bromate removal. F- and Fe-codoped TiO2 (F-Fe-TiO2) with a facet was successfully prepared, and its bromate-removal activity under visible light was examined. The microstructure, morphology, and chemical state of the doping elements and the optical property of the photocatalysts were examined using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), photoluminescence spectroscopy (PLS), and UV-Vis diffuse reflectance spectra (DRS). The results indicate that the optical properties of F-Fe-TiO2 with the facet and cuboid morphology were obviously improved and its photocatalytic activity was significantly enhanced. The bromate solution of 100 μg/L was thoroughly removed with 0.5 g/L dosage of 1.0% F- and 0.08% Fe-codoped TiO2 composite within 1 hour under visible light. Yan Zhang, Lingdan Li, and Hongyuan Liu Copyright © 2016 Yan Zhang et al. All rights reserved. Green Synthesis Methods of CoFe2O4 and Ag-CoFe2O4 Nanoparticles Using Hibiscus Extracts and Their Antimicrobial Potential Wed, 23 Nov 2016 13:57:08 +0000 The cobalt ferrite (CoFe2O4) and silver-cobalt ferrite (Ag-CoFe2O4) nanoparticles were obtained through self-combustion and wet ferritization methods using aqueous extracts of Hibiscus rosa-sinensis flower and leaf. X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and magnetic measurements were used for the characterization of the obtained oxide powders. The antimicrobial activity of the cobalt ferrite and silver-cobalt ferrite nanoparticles against Gram-positive and Gram-negative bacteria, as well as fungal strains, was investigated by qualitative and quantitative assays. The most active proved to be the Ag-CoFe2O4 nanoparticles, particularly those obtained through self-combustion using hibiscus leaf extract, which exhibited very low minimal inhibitory concentration values (0.031–0.062 mg/mL) against all tested microbial strains, suggesting their potential for the development of novel antimicrobial agents. Dana Gingasu, Ioana Mindru, Luminita Patron, Jose Maria Calderon-Moreno, Oana Catalina Mocioiu, Silviu Preda, Nicolae Stanica, Sultana Nita, Nicoleta Dobre, Marcela Popa, Gratiela Gradisteanu, and Mariana Carmen Chifiriuc Copyright © 2016 Dana Gingasu et al. All rights reserved. Synthesis of FeNi Alloy Nanomaterials by Proteic Sol-Gel Method: Crystallographic, Morphological, and Magnetic Properties Wed, 23 Nov 2016 08:32:27 +0000 Proteic Sol-Gel method was used for the synthesis of FeNi alloy at different temperature conditions and flow reduction. The solids were characterized by XRD, H2-TPR, SEM, TEM, Mössbauer spectroscopy, and VSM. It was observed by X-ray diffraction pure FeNi alloy in the samples reduced at 600°C (40 mL/min H2 flow) and 700°C (25 mL/min H2 flow). The FeNi alloy presented stability against the oxidizing atmosphere up to 250°C. The morphology exhibited agglomerates relatively spherical and particles in the range of 10–40 nm. Mössbauer spectroscopy showed the presence of disordered ferromagnetic FeNi alloy, and magnetic hysteresis loop revealed a typical behavior of soft magnetic material. Cássio Morilla dos Santos, Adanny Filipe Nogueira Martins, Bruna Carolina Costa, Thiago Soares Ribeiro, Tiago Pinheiro Braga, João Maria Soares, and José Marcos Sasaki Copyright © 2016 Cássio Morilla dos Santos et al. All rights reserved. Silicon Nanowires with MoSx and Pt as Electrocatalysts for Hydrogen Evolution Reaction Tue, 22 Nov 2016 08:01:45 +0000 A convenient method was used for synthesizing Pt-nanoparticle//silicon nanowires nanocomposites. Obtained Pt-/silicon nanowires electrocatalysts were characterized by transmission electron microscopy (TEM). The hydrogen evolution reaction efficiency of the Pt-/silicon nanowire nanocomposite catalysts was assessed by examining polarization and electrolysis measurements under solar light irradiations. The electrochemical characterizations demonstrate that Pt-/silicon nanowire electrodes exhibited an excellent catalytic activity for hydrogen evolution reaction in an acidic electrolyte. The hydrogen production capability of Pt-/silicon nanowires is also comparable to /silicon nanowires and Pt/silicon nanowires. Electrochemical impedance spectroscopy experiments suggest that the enhanced performance of Pt-/silicon nanowires can be attributed to the fast electron transfer between Pt-/silicon nanowire electrodes and electrolyte interfaces. S. H. Hsieh, S. T. Ho, and W. J. Chen Copyright © 2016 S. H. Hsieh et al. All rights reserved. Microwave-Assisted Hydrothermal Synthesis and Annealing of DyF3 Nanoparticles Mon, 21 Nov 2016 12:48:12 +0000 The series of DyF3 nanosized samples was synthesized by the colloidal chemistry method. The microwave-assisted hydrothermal treatment was used for the first time for the modification of DyF3 nanoparticles. Transmission electron microscopy images show that the DyF3 nanoparticles have average particle size of about 16–18 nm and the size distribution becomes narrower during the microwave irradiation. The X-ray diffraction analysis shows the narrowing of the diffraction peaks versus microwave treatment time. The experimental data demonstrates restructuring of the nanoparticles and their crystal structure becomes closer to the ideal DyF3 regular structure during the microwave irradiation of colloidal solution. The defect-annealing model of the microwave-assisted hydrothermal modification process is suggested. E. M. Alakshin, A. V. Klochkov, E. I. Kondratyeva, S. L. Korableva, A. G. Kiiamov, D. S. Nuzhina, A. A. Stanislavovas, M. S. Tagirov, M. Yu. Zakharov, and S. Kodjikian Copyright © 2016 E. M. Alakshin et al. All rights reserved. Mechanical Properties of Boehmite Evaluated by Atomic Force Microscopy Experiments and Molecular Dynamic Finite Element Simulations Sun, 20 Nov 2016 14:11:58 +0000 Boehmite nanoparticles show great potential in improving mechanical properties of fiber reinforced polymers. In order to predict the properties of nanocomposites, knowledge about the material parameters of the constituent phases, including the boehmite particles, is crucial. In this study, the mechanical behavior of boehmite is investigated using Atomic Force Microscopy (AFM) experiments and Molecular Dynamic Finite Element Method (MDFEM) simulations. Young’s modulus of the perfect crystalline boehmite nanoparticles is derived from numerical AFM simulations. Results of AFM experiments on boehmite nanoparticles deviate significantly. Possible causes are identified by experiments on complementary types of boehmite, that is, geological and hydrothermally synthesized samples, and further simulations of imperfect crystals and combined boehmite/epoxy models. Under certain circumstances, the mechanical behavior of boehmite was found to be dominated by inelastic effects that are discussed in detail in the present work. The studies are substantiated with accompanying X-ray diffraction and Raman experiments. J. Fankhänel, D. Silbernagl, M. Ghasem Zadeh Khorasani, B. Daum, A. Kempe, H. Sturm, and R. Rolfes Copyright © 2016 J. Fankhänel et al. All rights reserved. A Novel Discovery of Growth Process for Ag Nanowires and Plausible Mechanism Thu, 17 Nov 2016 14:27:50 +0000 A novel growth process of silver nanowires was revealed by tracing the morphology evolution of Ag nanostructures fabricated by an improved polyol process. A mixture of Ag nanowires and nanoparticles was obtained with the usage of PVP-K25 (MW = 38,000). The products sampled at different reaction time were studied in detail using UV-visible absorption spectra and transmission electron microscopy (TEM). An interesting phenomenon unknown in the past was observed where Ag nanoparticles undergo an important dissolution-recrystallization process and Ag nanowires are formed at the expense of the preformed Ag nanoparticles. A plausible novel growth mechanism for the silver nanowires was proposed. Jiejun Zhu, Caixia Kan, Yaozheng Wu, Jianguo Wan, Min Han, and Guanghou Wang Copyright © 2016 Jiejun Zhu et al. All rights reserved. Effect of Nanodiamonds on Structure and Durability of Polyethylene Oxide-Based Nanocomposites Wed, 16 Nov 2016 14:08:06 +0000 Polymer-based nanocomposites containing nanodiamonds (NDs) are attractive multifunctional materials with a growing range of applications. In this work, in the frame of developing completely biocompatible systems, nanocomposites based on polyethylene oxide (PEO) and different amount of NDs have been formulated through melt mixing and fully characterized. In particular, the reinforcement effect of NDs in PEO has been probed through tensile tests, and the rheological response of PEO-based nanocomposites as a function of the nanoparticles amount has been investigated and discussed. The obtained results show that the presence of well-distributed NDs strengthens the mechanical performance of the nanocomposites and brings about an increase of the PEO crystallinity, suggesting a strong adhesion between NDs and polymer matrix. Furthermore, as a result of NDs adding, alterations of the rheological behaviour of neat PEO can be noticed, as NDs are able to significantly influence the long-range dynamics of PEO chains. Besides, accelerated aging tests demonstrate that NDs show a remarkable protective ability against PEO photodegradation, due to their ability to attenuate efficiently UV radiation. The latter opens up new avenues for the use of NDs as multifunctional nanofillers for polymer-based nanocomposites with enhanced photooxidative resistance. Rossella Arrigo, Gabriele Ruisi, Rosalia Teresi, and Nadka Tzankova Dintcheva Copyright © 2016 Rossella Arrigo et al. All rights reserved. Electrochemiluminescence Biosensor Based on Thioglycolic Acid-Capped CdSe QDs for Sensing Glucose Wed, 16 Nov 2016 13:38:25 +0000 In order to detect low level glucose concentration, an electrochemiluminescence (ECL) biosensor based on TGA-capped CdSe quantum dots (QDs) was fabricated by the immobilization of CdSe QDs after modifying the surface of a glassy carbon electrode (GCE) with 4-aminothiophenol diazonium salts by the electrochemical method. For the detection of glucose concentration, glucose oxidase (GOD) was immobilized onto the fabricated CdSe QDs-modified electrode. The fabricated ECL biosensor based on TGA-capped CdSe QDs was characterized using a scanning electron microscope (SEM), UV-vis spectrophotometry, transmission electron microscopy (TEM), a fluorescence spectrometer (PL), and cyclic voltammetry (CV). The fabricated ECL biosensor based on TGA-capped CdSe QDs is suitable for the detection of glucose concentrations in real human blood samples. Eun-Young Jung, Jun-Hee Ye, Sung-Hee Jung, and Seong-Ho Choi Copyright © 2016 Eun-Young Jung et al. All rights reserved. Delivery Efficiency of miR-21i-CPP-SWCNT and Its Inhibitory Effect on Fibrosis of the Renal Mesangial Cells Wed, 16 Nov 2016 12:44:30 +0000 MicroRNA 21 (miR-21) was proved to cause renal fibrosis and the inhibition of miR-21 would improve the poor prognosis in renal cell carcinoma diseases. The complementary oligonucleotide of mature miR-21 was considered to be an effective intracellular miR-21 inhibitor (miR-21i). The directly effective delivery of miR-21i into fibrotic cell is a facile method for treatment of renal fibrosis. Herein, the miR-21i-CPP-SWCNT delivery system, synthesized via single-walled carbon nanotube (SWCNT) and cell-penetrating peptide (CPP), was taken as a novel fibrosis-targeting therapeutic carrier. The miR-21i and CPP firstly bind together via electrostatic forces, and subsequently miR-21i-CPP binds to the surface of SWCNTs via hydrophobic forces. CPP could endow the delivery system with targeting property, while SWCNT would enhance its penetrating ability. The exogenous miR-21i released from the designed miR-21i-CPP-SWCNTs had successfully inhibited the expression of fibrosis-related proteins in renal mesangial cells (RMCs). We found that the expression of TGF-β1 proteins was more sensitive to miR-21i-CPP-SWCNT than the expression of α-SMA proteins. Hong Liu, Guobao Wang, Yihong Yang, Lei Yu, Leyu Wang, Zhengda Wen, Xiaofang Hu, Hequn Zou, and Xiaozhong Qiu Copyright © 2016 Hong Liu et al. All rights reserved. Insights into Starch Coated Nanozero Valent Iron-Graphene Composite for Cr(VI) Removal from Aqueous Medium Wed, 16 Nov 2016 10:05:51 +0000 Embedding nanoparticles into an inert material like graphene is a viable option since hybrid materials are more capable than those based on pure nanoparticulates for the removal of toxic pollutants. This study reports for the first time on Cr(VI) removal capacity of novel starch stabilized nanozero valent iron-graphene composite (NZVI-Gn) under different pHs, contact time, and initial concentrations. Starch coated NZVI-Gn composite was developed through borohydrate reduction method. The structure and surface of the composite were characterized by scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and point of zero charge (pHpzc). The surface area and pHpzc of NZVI-Gn composite were reported as 525 m2 g−1 and 8.5, respectively. Highest Cr(VI) removal was achieved at pH 3, whereas 67.3% was removed within first few minutes and reached its equilibrium within 20 min obeying pseudo-second-order kinetic model, suggesting chemisorption as the rate limiting process. The partitioning of Cr(VI) at equilibrium is perfectly matched with Langmuir isotherm and maximum adsorption capacity of the NZVI-Gn composite is 143.28 mg g−1. Overall, these findings indicated that NZVI-Gn composite could be utilized as an efficient and magnetically separable adsorbent for removal of Cr(VI). Prasanna Kumarathilaka, Vimukthi Jayaweera, Hasintha Wijesekara, I. R. M. Kottegoda, S. R. D. Rosa, and Meththika Vithanage Copyright © 2016 Prasanna Kumarathilaka et al. All rights reserved. The Needs of Current Implant Technology in Orthopaedic Prosthesis Biomaterials Application to Reduce Prosthesis Failure Rate Wed, 16 Nov 2016 08:38:49 +0000 Today, orthopaedics is still in search for the most reliable biomaterial for prosthesis. The biomaterial needs to have good longevity and other supporting properties in order to maintain low implant failure. An ideal metallic biomaterial should be biocompatible, has similar elastic modulus to that of bone, has excellent resistance to fatigue, corrosion, aseptic loosening, and wear, and has good bone-bonding ability. The success of an implant depends on many factors. Good osseointegration is one of the factors required to reduce the rate of loosening of implants and in order to increase the chance of osseointegration, high stability of implants and early healing process encouragement are needed. Ahmad Jabir Rahyussalim, Aldo Fransiskus Marsetio, Ifran Saleh, Tri Kurniawati, and Yudan Whulanza Copyright © 2016 Ahmad Jabir Rahyussalim et al. All rights reserved. Advances in Nanoporous Materials Wed, 16 Nov 2016 06:18:35 +0000 Krishna Kant, Gurvinder Singh, and Mahaveer Kurkuri Copyright © 2016 Krishna Kant et al. All rights reserved. Synthesis of Highly Reduced Graphene Oxide for Supercapacitor Tue, 15 Nov 2016 14:29:42 +0000 A facile method to synthesize highly reduced graphene oxide in solid phase was developed. The reduced graphene oxide was scarcely prepared in solid phase. Solid substances act as spacers and pillaring agents. Sheets can not be close to each other in reduction process, and sheets agglomeration might not form. After reduction reaction is complete, the spacers and pillaring agents are removed. The average interlayer spacing and surface area of product are bigger than those of reduced graphene oxide. The product has few-layered sheet, and the ratio of carbon to oxygen is high, which might imply that the product is more similar to graphene compared to reduced graphene oxide. The specific capacitance of product is almost three times higher than that of reduced graphene oxide at the same current density. Chubei Wang, Jianwei Zhou, and Feipeng Du Copyright © 2016 Chubei Wang et al. All rights reserved. In Situ Atomistic Deformation Mechanisms Study of Nanowires Tue, 15 Nov 2016 14:19:50 +0000 “Smaller is stronger,” sub-, micro-, and nanomaterials exhibit high strength, ultralarge elasticity and unusual plastic and fracture behaviors which originate from their size effect and the low density of defects, different from their conventional bulk counterparts. To understand the structural evolution process under external stress at atomic scale is crucial for us to reveal the essence of these “unusual” phenomena and is momentous in the design of new materials. Our review presents the recent developments in the methods, techniques, instrumentation, and scientific progress of atomic scale in situ deformation dynamics on single crystalline nanowires. The super-large elasticity, plastic deformation mechanism transmission, and unusual fracture behavior related to the experimental mechanics of nanomaterials are reviewed. In situ experimental mechanics at the atomic scale open a new research field which is important not only to the microscopic methodology but also to the practice. Yonghai Yue, Qihua Gong, and Qi Zhang Copyright © 2016 Yonghai Yue et al. All rights reserved. Smart Polymeric Nanocarriers Tue, 15 Nov 2016 13:18:17 +0000 Jianxun Ding, Yilong Cheng, Mingqiang Li, Ruxandra Gref, and Xuesi Chen Copyright © 2016 Jianxun Ding et al. All rights reserved. Fabrication and Super-Antibacterial Property of Nanosilver/Sericin/Poly(ethylene oxide) Nanofibers through Electrospinning-Combined Postdeposition Method Tue, 15 Nov 2016 12:18:52 +0000 Nanosilver particle has been used in the nanofiber mats by mixing the nanosilver with the spinning solution for improving the antibacterial property. Although studies have shown that the antibacterial property of nanofiber mats gets increasing, the higher silver content and the larger released resistance of nanosilver from nanofiber mats are obvious. Here, the electrospinning-combined postdeposition method was used to prepare the nanosilver/sericin/poly(ethylene oxide) (Ag/SS/PEO) nanofiber mats and the bacterial reduction rates against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were analyzed. We found that the Ag/SS/PEO nanofiber mats were excellent antibacterial properties at the lower silver content and the bacterial reduction rates against S. aureus and E. coli all reached above 99.99%. Our data suggests that the antibacterial property can be improved by introducing the electrospinning-combined postdeposition method. Jia Li, Bo-Xiang Wang, Yi-Fan Cui, Zhi-Cai Yu, Xu Hao, Feng-Yuan Huang, De-Hong Cheng, and Yan-Hua Lu Copyright © 2016 Jia Li et al. All rights reserved. Functional Nanomaterials for Energy Conversion and Storage Tue, 15 Nov 2016 07:35:39 +0000 Tianyi Kou, Gongming Wang, Xihong Lu, Yang Song, and Teng Zhai Copyright © 2016 Tianyi Kou et al. All rights reserved. SPR Biosensing MUA/Poly-L-lysine Platform for the Detection of 2,4-Dinitrophenol as Small Molecule Model System Mon, 14 Nov 2016 13:47:49 +0000 Surface Plasmon Resonance assays are being developed as alternative biodetection methods for a great number of pesticides and toxins. These substances typically have low molecular weight, making it necessary to perform competitive inhibition immunoassays. In most of the cases, the strategy is to immobilize a protein derivative of the analyte, which usually involves the appearance of nonspecific protein binding which limits the detection range of the assay. In this work we present results of a poly-L-lysine (Au-MUA-PLL) based sensor platform for quantitative determination of 2,4-dinitrophenol as model system for small molecular weight substances detection. The prepared sensor chip was characterized by means of Atomic Force Microscopy, Surface Plasmon Resonance, and Surface Enhanced Raman Spectroscopy. Experiments verified the absence of nonspecific protein adsorption to Au-MUA-PLL surfaces and the improvement of the competitive inhibition assays performance in comparison with single and mixed thiol self-assembled monolayers. The possibility of directly immobilizing 2,4-dinitrophenol to the poly-L-lysine containing platforms leads to an improvement in the detection of the soluble analyte by the competitive inhibition assay avoiding undesirable nonspecific protein adsorption. Therefore, Au-MUA-PLL surfaces constitute a suitable alternative for quantitative detection of small molecules when nonspecific adsorption cannot be avoided. M. Antonieta Daza Millone, Eduardo A. Ramirez, Cecilia Y. Chain, Andrea Crivaro, David Romanin, Martín Rumbo, Guillermo Docena, Mauro D. Cocco, María L. Pedano, Alejandro Fainstein, Jorgelina Montoya, María E. Vela, and R. C. Salvarezza Copyright © 2016 M. Antonieta Daza Millone et al. All rights reserved. Effect of Hydrogen Peroxide Content on the Preparation of Peroxotitanate Materials for the Treatment of Radioactive Wastewater Mon, 14 Nov 2016 12:22:25 +0000 The modification of peroxotitanate using hydrogen peroxide significantly improved the ion-exchange capacity of titanate materials as sorbents for metal ions contained in a radioactive waste simulant solution. The effects of hydrogen peroxide content (hydrogen peroxide/titanium isopropoxide molar ratios, hereafter expressed as H/T) on the properties of as-prepared titanate synthesized at 130°C and at pH of 6-7, followed by freeze-drying, were investigated. The peroxotitanate materials thus obtained were characterized by XRD, BET, SEM, TEM, EDX, ICP, and Raman spectroscopy. At an H/T ratio of 2, peroxotitanate predominantly exhibited an amorphous structure, with a clearly observed tubular or fibrous structure. Furthermore, peroxotitanate modified at an H/T ratio of 2 exhibited the best ion-exchange capacity of 191 mg g−1 for metal ions contained in a radioactive waste simulant solution. Hence, these peroxotitanate materials are suitable for removing metal ions from wastewater, especially lanthanide ions (Ln3+) and Sr2+. Wein-Duo Yang, Chau Thanh Nam, Jen-Chien Chung, and Hsin-Ya Huang Copyright © 2016 Wein-Duo Yang et al. All rights reserved. Synthesis and Characterization of Nontoxic Hollow Iron Oxide (-) Nanoparticles Using a Simple Hydrothermal Strategy Mon, 14 Nov 2016 09:49:11 +0000 Hollow spheres of iron oxide (α-Fe2O3) were successfully synthesized in a simple one-pot synthesis by using hydrothermal method. Iron salt was dissolved together with glucose in water and then the mixture was heated to 180°C in an autoclave at 12 and 24 hours of synthesis time separately. Carbon spheres were formed with the metal ions into their hydrophilic shell after the hydrothermal approach. Hollow α-Fe2O3 spheres of around 200 to 300 nm size were formed after the calcination that lead to the removal of carbon. Size of nanoparticles, surface area, and thickness of the α-Fe2O3 shell can be precisely controlled by controlling the ratio of iron and glucose. Increasing the reaction time will decrease the shell thickness. Phase confirmation and crystalline structure of these nanoparticles were done by XRD. Surface morphology was characterized by SEM and TEM analysis showed the hollow spheres inside and a shell of α-Fe2O3. Further confirmation was done by EDX and FTIR analysis. Iron content was measured by ICP-OES. Cytotoxicity was done by using CCK-8 assay kit in the Hep G-2 cell line showing the nontoxic behavior of α-Fe2O3 nanoparticles. The as-prepared nanoparticles can be exploited in a number of applications in areas ranging from medicine to pharmaceutics to material science. Rabia Riasat and Guangjun Nie Copyright © 2016 Rabia Riasat and Guangjun Nie. All rights reserved. Nanocomposites of Magnetite and Layered Double Hydroxide for Recyclable Chromate Removal Sun, 13 Nov 2016 14:14:38 +0000 Nanocomposites containing magnetic iron oxide (magnetite) nanoparticles and layered double hydroxide (LDH) nanosheets were prepared by two different methods, exfoliation-reassembly and coprecipitation, for aqueous chromate adsorbent. According to X-ray diffraction, scanning electron microscopy, and atomic force microscopy, both nanocomposites were determined to develop different nanostructures; LDH nanosheets well covered magnetite nanoparticles with house-of-cards-like structure in exfoliation-reassembly method, while coprecipitation resulted in LDH particle formation along with magnetite nanoparticles. Zeta-potential measurement also revealed that the magnetite surface was effectively covered by LDH moiety in exfoliation-reassembly compared with coprecipitation. Time, pH, concentration dependent chromate adsorption tests, and magnetic separation experiments exhibited that both nanocomposites effectively adsorb and easily collect chromate. However, exfoliation-reassembly nanocomposite was determined to be slightly effective in chromate removal by ~10%. Chromate adsorbed nanocomposites could be regenerated by treating with bicarbonate and the regenerated nanocomposites preserved ~80% of chromate adsorption efficacy after three times of recycling. Gyeong-Hyeon Gwak, Min-Kyu Kim, and Jae-Min Oh Copyright © 2016 Gyeong-Hyeon Gwak et al. All rights reserved. Molecular Dynamics Simulation of Nanoindentation of Cu/Au Thin Films at Different Temperatures Sun, 13 Nov 2016 12:18:51 +0000 Two methods, deposition method and ideal modeling based on lattice constant, are used to prepare three modulation periods’ (1.8 nm Cu/3.6 nm Au, 2.7 nm Cu/2.7 nm Au, and 3.6 nm Cu/1.8 nm Au) thin films for nanoindentation at different temperatures. The results show that the temperature will weaken the hardness of thin films. The deposition method and the formation of coherent interface will result in a lot of defects in thin films. These defects can reduce the residual stress in the thin films which is caused by the external force. The proposed system will provide potential benefits in designing the microstructures for thin films. Qibin Li, Cheng Huang, Yunpei Liang, Tao Fu, and Tiefeng Peng Copyright © 2016 Qibin Li et al. All rights reserved. Effect of Nanoparticle Surface Modification and Filling Concentration on Space Charge Characteristics in TiO2/XLPE Nanocomposites Sun, 13 Nov 2016 06:42:10 +0000 This paper focuses on the space charge characteristics in TiO2/cross-linked polyethylene (XLPE) nanocomposites; the unmodified and modified by dimethyloctylsilane (MDOS) TiO2 nanoparticles were added to XLPE matrix with different mass concentrations (1 wt%, 3 wt%, and 5 wt%). The scanning electron microscope (SEM) showed that the MDOS coupling agent could improve the compatibility between TiO2 nanoparticles and XLPE matrix to some extent and reduce the agglomeration of TiO2 nanoparticles compared with unmodified TiO2 nanoparticles; the volume resistivity testing indicated that the volume resistivity of TiO2/XLPE nanocomposites was higher than Pure-XLPE and increased with the increase of filling concentrations. According to the pulsed electroacoustic (PEA) measurements, it was concluded that the space charge accumulation was suppressed by filling TiO2 nanoparticles and the distribution of electric field in samples was improved greatly. In addition, it was found that the injection of homocharge was more obvious in MDOS-TiO2/XLPE than that in UN-TiO2/XLPE and the homocharge injection decreased with the increase of filling concentration. Youyuan Wang, Kun Xiao, Can Wang, Lijun Yang, and Feipeng Wang Copyright © 2016 Youyuan Wang et al. All rights reserved. Facile Synthesis Polyethylene Glycol Coated Magnetite Nanoparticles for High Colloidal Stability Thu, 10 Nov 2016 10:06:00 +0000 Polyethylene glycol (PEG) is one of the most frequently used synthetic polymers for surface modifications of magnetite nanoparticles (MNPs) to provide a new opportunity for constructing high colloidal stability. Herein, a facile in situ coprecipitation technique is described for the synthesis of PEG coated MNPs using ammonium hydroxide as the precipitating agent. The structure and morphology of the prepared PEG coated MNPs samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray spectroscopy, thermogravimetric analysis (TGA), and the high resolution transmission electron microscopy (HRTEM). In this study, all samples demonstrated hydrodynamic size in the range of 32 to 43 nm with narrow size distribution. In addition, the magnetic properties of resultant samples were investigated using a vibrating sample magnetometer (VSM) to reveal the superparamagnetic behaviour with saturation magnetization. The saturation magnetization of PEG coated MNPs samples was in the range of 63 to 66 emu/g at 300 K. Interestingly, it was found that 1.0 g of PEG coated MNPs exhibited high colloidal stability in a basic solution (pH = 10) and nitrile (NBR) latex up to 21 days as compared to the unmodified MNPs during the sedimentation test. Mun Foong Tai, Chin Wei Lai, and Sharifah Bee Abdul Hamid Copyright © 2016 Mun Foong Tai et al. All rights reserved.