Journal of Nanomaterials The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Characterization of Ag-Doped p-Type SnO Thin Films Prepared by DC Magnetron Sputtering Mon, 18 Dec 2017 00:00:00 +0000 Crystalline structure and optoelectrical properties of silver-doped tin monoxide thin films with different dopant concentrations prepared by DC magnetron sputtering are investigated. The X-ray diffraction patterns reveal that the tetragonal SnO phase exhibits preferred orientations along (101) and (110) planes. Our results indicate that replacing Sn2+ in the SnO lattice with Ag+ ions produces smaller-sized crystallites, which may lead to enhanced carrier scattering at grain boundaries. This causes a deterioration in the carrier mobility, even though the carrier concentration improves by two orders of magnitude due to doping. In addition, the Ag-doped SnO thin films show a p-type semiconductor behavior, with a direct optical gap and decreasing transmittance with increasing Ag dopant concentration. Hoai Phuong Pham, Thanh Giang Le Thuy, Quang Trung Tran, Hoang Hung Nguyen, Huynh Tran My Hoa, Hoang Thi Thu, and Tran Viet Cuong Copyright © 2017 Hoai Phuong Pham et al. All rights reserved. Synthesis and Bactericidal Properties of Hyaluronic Acid Doped with Metal Nanoparticles Sun, 17 Dec 2017 08:34:10 +0000 A study on the nanoparticles size and the antibacterial properties of hyaluronic acid (HA) doped with nanoparticles is reported. Nanoparticles from gold, silver, copper, and silver palladium with HA support were performed. The solvated metal atom dispersion (SMAD) method with 2-propanol and HA was used. High-resolution transmission electron microscopy (HRTEM), infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA) were conducted. The average sizes of nanoclusters were as follows: HA-Au = 17.88 nm; HA-Ag = 50.41 nm; HA-Cu = 13.33 nm; and HA-AgPd = 33.22 nm. The antibacterial activity of solutions and films containing nanoparticles against American Type Culture Collection (ATCC) bacterial strains Escherichia coli (EC), Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), and Pseudomonas aeruginosa (PA) was determined. Inhibition was observed for HA-Ag, HA-Cu, and HA-AgPd. Toxicological tests were performed in rats that were injected intraperitoneally with two concentrations of gold, copper, silver, and silver-palladium nanoparticles. No alterations in hepatic parameters, including ALT (alanine aminotransferase), GGT (gamma-glutamyl transpeptidase) bilirubin, and albumin, were observed after 14 days. These films could be used as promoters of skin recovery and Grades I and II cutaneous burns and as scaffolds. Galo Cárdenas-Triviño, Macarena Ruiz-Parra, Luis Vergara-González, Javier Ojeda-Oyarzún, and Guillermo Solorzano Copyright © 2017 Galo Cárdenas-Triviño et al. All rights reserved. Fabrication, Characterization, and In Vivo Evaluation of Famotidine Loaded Solid Lipid Nanoparticles for Boosting Oral Bioavailability Thu, 14 Dec 2017 07:39:59 +0000 Famotidine as H2 receptor has antagonistic effects on gastric secretion. Unfortunately, its hydrophobic nature contributes to its variable and poor oral bioavailability. In the current study efforts are being made to fabricate famotidine loaded solid lipid nanoparticles with narrow size distribution. Prepared nanoformulations were pharmaceutically evaluated to confirm the desired boosted oral bioavailability. Famotidine loaded nanoformulation (FFSe-4) showed particle size  nm, polydispersity index , zeta potential − mV, entrapment efficiency %, and drug loading capacity %. Drug-excipients compatibility was confirmed by Fourier transformed infrared spectroscopy. Scanning electron microscopy confirmed spherical shaped, nanosized particles. Differential scanning calorimetry and powder X-ray diffractometry confirmed the change in crystalline nature. Prepared nanoformulation was more stable at refrigerated temperature. In vitro study showed that drug release time is proportional to drug pay load and followed zero order kinetics. Release exponent () confirmed non-Fickian-diffusion mechanism for drug release. In vivo pharmacokinetic studies showed 2.06-fold increase in oral bioavailability of famotidine dispersed in solid lipid nanoparticles compared to commercial product. These results authenticate solid lipid nanoparticles as drug delivery system and propose prolonged release with improved oral bioavailability for famotidine. Muhammad Shafique, Mir Azam Khan, Waheed S. Khan, Maqsood-ur-Rehman, Waqar Ahmad, and Shahzeb Khan Copyright © 2017 Muhammad Shafique et al. All rights reserved. Practical Solution for Effective Whole-Body Magnetic Fluid Hyperthermia Treatment Wed, 13 Dec 2017 00:00:00 +0000 Magnetic fluid hyperthermia therapy is considered as a promising treatment for cancers including unidentifiable metastatic cancers that are scattered across the whole body. However, a recent study on heat transfer simulated on a human body model showed a serious side effect: occurrences of hot spots in normal tissues due to eddy current loss induced by variation in the irradiated magnetic field. The indicated allowable upper limit of field amplitude for constant irradiation over the entire human body corresponded to approximately 100 Oe at a frequency of 25 kHz. The limit corresponds to the value of 2.5 × 106 Oe·s−1 and is significantly lower than the conventionally accepted criteria of 6 × 107 Oe·s−1. The present study involved evaluating maximum performance of conventional magnetic fluid hyperthermia cancer therapy below the afore-mentioned limit, and this was followed by discussing alternative methods not bound by standard frameworks by considering steady heat flow from equilibrium responses of stable nanoparticles. Consequently, the clarified potentials of quasi-stable core-shell nanoparticles, dynamic alignment of easy axes, and short pulse irradiation indicate that the whole-body magnetic fluid hyperthermia treatment is still a possible candidate for future cancer therapy. Hiroaki Mamiya, Yoshihiko Takeda, Takashi Naka, Naoki Kawazoe, Guoping Chen, and Balachandran Jeyadevan Copyright © 2017 Hiroaki Mamiya et al. All rights reserved. Preparation and Characterization of Folate-Targeted Fe3O4 Nanoparticle Codelivering Cisplatin and TFPI-2 Plasmid DNA for Nasopharyngeal Carcinoma Therapy Tue, 12 Dec 2017 00:00:00 +0000 A novel folate (FA) receptor-targeted superparamagnetic Fe3O4 nanoparticles (SPIONs) codelivering cisplatin (CDDP) and tissue factor pathway inhibitor-2 (TFPI-2) plasmid DNA (pDNA) was constructed. The core shell nanocomposites (FA-PEG-PEI@SPION-CDDP-TFPI-2) were composed of superparamagnetic Fe3O4 core that binds CDDP and TFPI-2 shell that combines with folate-polyethylene glycol-polyethyleneimine (FA-PEG-PEI) via electrostatic interaction. The shell containing FA-PEG-PEI and TFPI-2 plasmid was synthesized through amidation reaction and electrostatic adsorption and the core containing SPION-CDDP was modified by aldehyde sodium alginate. Proton nuclear magnetic resonance and Fourier transform infrared spectra on FA-PEG-PEI polymers showed characteristic peaks of various metabolites in corresponding frequency. Transmission electron microscopy image of FA-PEG-PEI@SPION-CDDP-TFPI-2 nanoparticles demonstrated a near-monodisperse spherical morphology, while dynamic light scattering studies indicated an intensity-average diameter of 149.5 nm. Zeta potential was 14.89 ± 1.83 mv and the final concentration of loaded CDDP was 100 ug/ml. Gel electrophoresis data showed that the nanocomposite would protect TFPI-2 pDNA from being digested by DNases. Compared with CNE-2 cells, the good targetability and better gene transfection efficiency (57.9%) were detected by Prussian blue iron stain and fluorescence analysis in HNE-1 cells in vitro. The results suggested the potential application of FA-PEG-PEI@SPION-CDDP-TFPI-2 as a multifunctional anticancer nanomedicine on targeting therapy for FR positive NPC. Juan Zhang, Huanhuan Weng, Xiangwan Miao, Quanming Li, Siqi Wang, Huifen Xie, Tao Liu, and Minqiang Xie Copyright © 2017 Juan Zhang et al. All rights reserved. Enhanced Thermal Conductivity for Nanofluids Containing Silver Nanowires with Different Shapes Sun, 10 Dec 2017 00:00:00 +0000 Nanofluids are the special agents to enhance the heat transfer property of the common fluids, and most of the thermal additives are the spherical nanoparticles. Up to now, the 1D thermal additives are not well exploited. In this paper, a kind of silver nanowires (AgNWs) with well-distributed shape and aspect ratio is synthesized. The results show that when we use the AgNWs prepared by the poly-vinyl-pyrrolidone (PVP) with a specific molecular weight of 40000, the thermal conductivity enhancement of nanofluids prepared by that kind of silver nanowires is as high as 13.42% when loading 0.46 vol.% AgNWs, and the value of the thermal conductivity is 0.2843 W/m·K, which is far more than the case when loading the same volume of spherical silver particles. Besides, we use H&C model to fit the experimental results and the experimental results are consistent with the model. Liye Zhang, Wei Yu, Dahai Zhu, Huaqing Xie, and Guiwen Huang Copyright © 2017 Liye Zhang et al. All rights reserved. Making Marble Powder Waste Profitable by Using Nano-TiO2 Surface Modification for Air Quality Improvement Applications Sun, 10 Dec 2017 00:00:00 +0000 We report a brand new recycling route of waste marble powder, by means of surface modification with homemade nano-TiO2 particles to produce low cost coating materials for the application in air quality improvement. The as-prepared nano-TiO2 in anatase phase exhibits excellent photocatalytic characteristic, reflected by the high degradation rate of over 95% of methylene blue within 6 hours of UV irradiation. The prepared coating consisting of nano-TiO2 clad marble powder was tested by monitoring the decomposition rate of formaldehyde gas. A high degradation efficiency of about 95% within 9 hours of illumination is achieved, demonstrating a promising potential for removing the harmful and toxic organic pollutants in air while applying this coating in buildings both interiorly and exteriorly. Yaxiong Ji, Xing Rong, Hong Zhong, Yuanhao Wang, Shifeng Wang, and Lin Lu Copyright © 2017 Yaxiong Ji et al. All rights reserved. New Method for the Development of Plasmonic Metal-Semiconductor Interface Layer: Polymer Composites with Reduced Energy Band Gap Thu, 07 Dec 2017 06:35:55 +0000 Silver nanoparticles within a host polymer of chitosan were synthesized by using in situ method. Ultraviolet-visible spectroscopy was then carried out for the prepared chitosan : silver triflate (CS : AgTf) samples, showing a surface plasmonic resonance (SPR) peak at 420 nm. To prepare polymer composites with reduced energy band gap, different amounts of alumina nanoparticles were incorporated into the CS : AgTf solution. In the present work, the results showed that the reduced silver nanoparticles and their adsorption on wide band gap alumina (Al2O3) particles are an excellent approach for the preparation of polymer composites with small optical band gaps. The optical dielectric loss parameter has been used to determine the band gap experimentally. The physics behind the optical dielectric loss were interpreted from the viewpoint of quantum mechanics. From the quantum-mechanics viewpoint, optical dielectric loss was also found to be a complex equation and required lengthy numerical computation. From the TEM investigation, the adsorption of silver nanoparticles on alumina has been observed. The optical micrograph images showed white spots (silver specks) with different sizes on the surface of the films. The second semicircle in impedance Cole-Cole plots was found and attributed to the silver particles. Shujahadeen B. Aziz, Soran M. Mamand, Salah R. Saed, Ranjdar M. Abdullah, and Sarkawt A. Hussein Copyright © 2017 Shujahadeen B. Aziz et al. All rights reserved. The Effect of High Loaded Multiwall Carbon Nanotubes in Natural Rubber and Their Nonlinear Material Constants Sun, 03 Dec 2017 08:05:03 +0000 The aim of this paper is to study the high load of multiwall carbon nanotubes (MWCNTs) in natural rubber (NR) matrix. Firstly, the rubber matrix, fillers, and crosslinker are thoroughly mixed together in two-roll mill. Rheological tests are done from which scorch time, cure time, and cure index are estimated. The kneaded mixer is then compression molded, dumb bell samples as per ASTM D412 are prepared, and tensile strength, tensile modulus, elongation at break, and hardness are measured. It is noticed that NR/30% MWCNT has shown the highest tensile strength of 23.38 MPa and Shore A hardness of 90, which is 78.18% and 91.5%, respectively, higher than the unfilled NR. The increase in strength and hardness, the ductility loss, and decrease in elongation at break are observed upon increase in filler. FTIR, SEM, and AFM examinations are done and the results show high dispersion of nanofillers and strong interfacial interaction with rubber, which is responsible for overall enhancement in mechanical properties of the nanocomposites. Furthermore, the nonlinear material constants are evaluated through extended tube model and corresponding nonlinear material constants of different filler compositions are presented for the designers to use them in their component design and analysis. Natarajan Elango, N. Srinivasa Gupta, Yu Lih Jiun, and Alireza Golshahr Copyright © 2017 Natarajan Elango et al. All rights reserved. Synthesis of ZnO Nanopowders by the Homogeneous Precipitation Method: Use of Taguchi’s Method for Analyzing the Effect of Different Variables Wed, 29 Nov 2017 09:04:34 +0000 In the present work the effect of different factors in the synthesis of ZnO powders by the homogeneous precipitation method is analyzed. A robust statistical technique, Taguchi’s method, was used to reduce the experiments number. The variables studied were precursor, solvent and precipitating agent type, Zn molar concentration, percentage of saturation, speed and time of agitation, and temperature of synthesis. In order to optimize the particle size, an experimental design of 18 trials was proposed, according to L18 Taguchi array. Structural and morphological properties were characterized by X-ray diffraction (XRD) and scanning and transmission electron microscopy techniques (SEM and TEM). The estimated crystallite size in synthesized samples ranged from 32 to 57 nm. The morphologies obtained presented several forms, such as spheres, wires, flowers, bars, and tetrahedrons, with a particle size variation of 35 to 165 nm. In this work it is shown that using a statistical experimental design leads us to a fast and reliable optimization of the synthesis parameters for obtaining small size ZnO nanoparticles, thus optimizing time and human and materials resources. R. Herrera-Rivera, M. de la L. Olvera, and A. Maldonado Copyright © 2017 R. Herrera-Rivera et al. All rights reserved. Temperature Effects on Tensile and Compressive Mechanical Behaviors of C-S-H Structure via Atomic Simulation Wed, 29 Nov 2017 08:17:58 +0000 An atomic scale model of amorphous calcium silicate hydrate (C-S-H) with Ca/Si ratio of 1.67 is constructed. Effects of temperature on mechanical properties of C-S-H structure under tensile and compressive loading in the layered direction are investigated via molecular dynamics simulations. Results from present simulations show that (1) the tensile strength and Young’s modulus of C-S-H structure significantly decrease with the increase of the temperature; (2) the water layer plays an important role in the mechanical properties of C-S-H structure; (3) the compressive strength is stronger than tensile strength, which corresponds with the characteristic of cement paste. Hao Xin, Weihui Lin, Jia Fu, Wu Li, and Zhihua Wang Copyright © 2017 Hao Xin et al. All rights reserved. Green Method for Synthesis of Gold Nanoparticles Using Polyscias scutellaria Leaf Extract under UV Light and Their Catalytic Activity to Reduce Methylene Blue Tue, 28 Nov 2017 08:04:54 +0000 The aqueous fraction of Polyscias scutellaria leaf extract (PSE) has been used as a reducing agent and stabilizer in the green synthesis of gold nanoparticles (AuNPs). UV-Vis spectrophotometry, particle size analyzer (PSA), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy-selected area electron diffraction (TEM-SAED), and X-ray diffraction (XRD) were used to characterize AuNPs. The AuNPs have a size of 5–20 nm and have a face centered cubic (fcc) crystal structure and are stable for 21 days. Phenolic compounds, which are secondary metabolites of PSE, act as an active compound to reduce Au3+ ion to Au0, as well as stabilize the AuNPs through their surface interaction with carbonyl and hydroxyl groups of phenols. AuNPs exhibit excellent catalytic activity for the reduction of methylene blue with NaBH4. The reduction of methylene blue using AuNPs catalysts is a pseudo-first-order reaction with a reduction rate constant () of 0.0223 min−1. Yoki Yulizar, Tresye Utari, Harits Atika Ariyanta, and Digha Maulina Copyright © 2017 Yoki Yulizar et al. All rights reserved. Preparation of Modified Red Mud-Supported Fe Catalysts for Hydrogen Production by Catalytic Methane Decomposition Mon, 27 Nov 2017 00:00:00 +0000 A modified red mud- (MRM-) supported Fe catalyst (Fe/MRM) was prepared using the homogeneous precipitation method and applied to methane decomposition to produce hydrogen. The TEM and SEM-EDX results suggested that the particle sizes of the Fe/MRM catalysts were much smaller than that of raw red mud (RM), and the active metal Fe was evenly distributed over the catalyst structure. Moreover, BET results indicated that the surface areas and pore volumes of the catalysts were significantly improved, and the pore sizes of Fe/MRM were distributed from 5 to 12 nm, which is typical for a mesoporous material. The activities of those catalysts for the catalytic decomposition of methane were studied at atmospheric pressure at a moderate temperature of 650°C; the results showed that the Fe/MRM catalysts were more active than RM and MRM. The methane conversion curves of Fe/MRM catalysts exhibited similar variation tendencies (three-step) during the reaction despite different Fe contents, and the loading amount of Fe clearly affected the activity of the catalysts. Quanrun Liu, Haipeng Li, Xiaoke Fang, Jingjie Zhang, Chuanxiang Zhang, Mingjie Ma, Fenghai Li, and Guangxu Huang Copyright © 2017 Quanrun Liu et al. All rights reserved. Noncovalent Spiropyran Coatings for Photoinduced Wettability Switching Sun, 26 Nov 2017 07:24:09 +0000 The noncovalent binding of spiropyran to candle-soot-covered surfaces is investigated for wettability switching using a coating procedure realized with a drop casting process of using 0.001 mol/L spiropyran in a 5 : 1 toluene-acetone mixture. Scanning electron microscopy images reveal a resulting surface with spiropyran flakes in the candle soot. A reversible switching with UV light and blue or green light is achieved, starting from an initial contact angle of 130°  ± 9.68°. The highest contact angle difference is 41° and reversibility has been shown for several switching cycles. Hence, our methods provide an easy-to-use strategy to generate surfaces with switchable wettability. Matthias Bremer, Ruprecht Reinke, Britta Hesseler, Mohammadreza Taale, Daniela Ingwersen, Stefan Schwarzer, Christine Selhuber-Unkel, and Martina Gerken Copyright © 2017 Matthias Bremer et al. All rights reserved. Facile Synthesis and Special Phase Transformation of Hydrophilic Iron Oxides Nanoparticles Thu, 23 Nov 2017 00:00:00 +0000 Superparamagnetic iron oxide nanoparticles (SPIONs), -Fe2O3, with hydrophilic surfaces are fabricated in ethylene glycol solutions, without surfactant or additive, by solvothermal process from -Fe2O3 nanoparticle as precursors. With the addition of a trace of hydrazine hydrate, the cubic phase Fe3O4 nanoparticles are obtained instead of γ-Fe2O3. The saturation magnetization value of γ-Fe2O3 nanoparticles is up to 74.3 emu/g. This study provides a low cost, safe, and universal route to serve as excellent biocompatibility magnetic core for future applications in biomedical, agriculture, and horticulture applications. Liqiao Chen, Yunqian Long, Zhe Leng, Jinfei Hu, Xuan Yu, and Xiaoming Yu Copyright © 2017 Liqiao Chen et al. All rights reserved. Buffer Film Assisted Growth of Dense MWCNTs on Copper Foils for Flexible Electrochemical Applications Tue, 21 Nov 2017 10:11:20 +0000 The novel Inconel buffer films were prepared on copper foils using unbalance direct current (DC) magnetron sputtering. These films were employed as buffer layers for supporting the dense growth of multiwalled carbon nanotubes (MWCNTs). Thermal chemical vapor deposition (CVD) with metal alloys such as stainless steel (SS) type 304 films was considered to synthesize MWCNTs. To understand the effectiveness of these buffer films, the MWCNTs grown on buffer-free layer were carried out as a comparison. The main problem such as the diffusion of catalysts into the oxide layer of metal substrate during the CVD process was solved together with a creation of good electrical contact between substrate and nanotubes. The morphologies, crystallinities, and electrochemical behaviors of MWCNTs grown on Inconel buffer films with 304 SS catalysts revealed the better results for applying in flexible electrochemical applications. Udomdej Pakdee and Boonchai Duangsawat Copyright © 2017 Udomdej Pakdee and Boonchai Duangsawat. All rights reserved. Evaluation of the Osteoblast Behavior to PGA Textile Functionalized with RGD as a Scaffold for Bone Regeneration Mon, 20 Nov 2017 09:44:17 +0000 The new era of biomaterials for repairing bone tissue injury continues to be a challenge in bone tissue engineering. The fiber scaffolds allow for cellular interconnection and a microenvironment close to the bone extracellular matrix. The aim of this study was to evaluate the osteoblast behavior on a 3D textile of PGA (polyglycolic acid) fibers functionalized with the RGD (R: arginine; G: glycine; D: aspartic acid) peptide. The cell morphology, proliferation, and calcium phosphate deposition ability were evaluated on textiles at different time intervals under a confocal laser scanning microscope. The osteoblast viability ranged from 92% to 98%, and cell proliferation was higher in PGA-RGD than control PGA (uncoated). In addition, the osteoblast calcium phosphate deposition was significantly greater on PGA-RGD in osteogenic inductor medium (OIM) in contrast to controls without inducing factors. The PGA-RGD fibers supported proliferation and viability of osteoblast and stimulated bone osteogenesis and mineralization. These results support the adoption of this 3D polymeric textile as a scaffold for bone tissue engineering. Mariné Ortiz, Diana María Escobar-Garcia, Marco Antonio Álvarez-Pérez, Amaury Pozos-Guillén, Christian Grandfils, and Héctor Flores Copyright © 2017 Mariné Ortiz et al. All rights reserved. Comparative Study on Properties of Polylactic Acid Nanocomposites with Cellulose and Chitin Nanofibers Extracted from Different Raw Materials Mon, 20 Nov 2017 09:20:32 +0000 Polylactic acid (PLA) was reinforced with ultralong cellulose and chitin nanofibers extracted from four raw materials by extrusion. The mechanical, rheological, thermal, and viscoelastic performances of four nanocomposites were comparatively studied in detail. The results showed that fibrillation of poplar was much easier than that of cotton, and fibrillation of crab shell was relatively hard as compared to prawn shell. The poplar CNFs/PLA composite exhibited the best mechanical properties among four nanocomposites due to the highest aspect ratio of nanofibers, while both the cotton CNFs/PLA composite and the crab shell CHNFs/PLA composite had low mechanical strength due to the relatively low aspect ratio. FE-SEM images showed that the ultralong nanofibers were uniformly dispersed in PLA matrix for all four samples with the water preblending method. The CTE values of the nanocomposites with 40 wt% nanofibers extracted from poplar, cotton, crab shell, and prawn shell were 69.5 × 10−6 K−1, 79.6 × 10−6 K−1, 77.2 × 10−6 K−1, and 75.3 × 10−6 K−1, respectively. All the results indicated that the aspect ratio of the nanofibers has a great influence on the performance of the composites, irrespective of the composites prepared by cellulose or chitin. Jingjing Li, Jian Li, Dejun Feng, Jingfeng Zhao, Jingrong Sun, and Dagang Li Copyright © 2017 Jingjing Li et al. All rights reserved. Continuous Synthesis of Ag/TiO2 Nanoparticles with Enhanced Photocatalytic Activity by Pulsed Laser Ablation Thu, 16 Nov 2017 10:59:55 +0000 A facile and environmental friendly synthesis strategy based on pulsed laser ablation has been developed for potential mass production of Ag-loaded TiO2 (Ag/TiO2) nanoparticles. By sequentially irradiating titanium and silver target substrates, respectively, with the same 1064 nm 100 ns fiber laser, Ag/TiO2 particles can be fabricated. A postannealing process leads to the crystallization of TiO2 to anatase phase with high photocatalytic activity. The phase composition, microstructure, and surface state of the elaborated Ag/TiO2 are characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. The results suggest that the presence of silver clusters deposited on the surface of TiO2 nanoparticles. The nanostructure is formed through laser interaction with materials. Photocatalytic activity evaluation shows that silver clusters could significantly enhance the photocatalytic activity of TiO2 in degradation of methylene blue (MB) under UV light irradiation, which is attributed to the efficient electron traps by Ag clusters. Our developed Ag/TiO2 nanoparticles synthesized via a straightforward, continuous, and green pathway could have great potential applications in photocatalysis. Rui Zhou, Shengdong Lin, Huixin Zong, Tingting Huang, Fengping Li, Jiahong Pan, and Jingqin Cui Copyright © 2017 Rui Zhou et al. All rights reserved. Synthesis of a High-Coercivity FePt–Ag Nanocomposite Magnet via Block Copolymer-Templated Self-Assembly Wed, 15 Nov 2017 00:00:00 +0000 Magnetic recording media are composed of magnetic thin films consisting of magnetically isolated crystallites. For practical use of magnetic particles as recording media, it will be necessary to realize high coercivity by fabricating nanocrystalline grains and forming grain boundaries with the nonmagnetic phase. In this study, a high-coercivity FePt–Ag nanocomposite magnet was synthesized by means of block copolymer-templated self-assembly. Precursors of Fe, Pt, and Ag were introduced into a polymer block, and the resulting material was oxidized and then reduced to form a nanocomposite consisting of FePt nanoparticles surrounded by a matrix of Ag. X-ray diffraction analysis revealed that the introduction of Ag did not significantly affect the crystalline ordering of the FePt. The addition of Ag increased the coercivity by 53% (from 11.1 to 17.0 kOe). Our results suggest that the grain boundaries of the nonmagnetic Ag metal acted as pinning sites, disrupting magnetic coupling between individual FePt nanocrystallites and hindering domain wall motion at an external magnetic field. Hiroaki Wakayama and Hirotaka Yonekura Copyright © 2017 Hiroaki Wakayama and Hirotaka Yonekura. All rights reserved. Effect of Gas Flowrate on Nucleation Mechanism of MWCNTs for a Compound Catalyst Tue, 14 Nov 2017 10:19:54 +0000 Activation of the catalyst particles during a CVD process can be anticipated from the carbon feeding rate. In this study, Fe2O3/Al2O3 catalyst was synthesized with uniformly dispersed iron over alumina support for onward production of multiwalled carbon nanotubes (MWCNTs) in a fluidized bed chemical CVD reactor. The effect of the ethylene flowrate on catalytic activity of the compound catalyst and morphology of the as-grown MWCNTs was also investigated in this study. The dispersed active phases of the catalyst and optimized gas flowrate helped in improving the tube morphology and prevented the aggregation of the as-grown MWCNTs. The flowrates, below 100 sccm, did not provide sufficient reactants to interact with the catalyst for production of defect-free CNT structures. Above 100 sccm, concentration of the carbon precursor did not show notable influence on decomposition rate of the gas molecules. The most promising results on growth and structural properties of MWCNTs were gained at ethylene flowrate of 100 sccm. At this flowrate, the ratio of and intensity peaks () was deliberated about 1.40, which indicates the growth of graphitic structures of MWCNTs. S. Shukrullah, N. M. Mohamed, Y. Khan, M. Y. Naz, A. Ghaffar, and I. Ahmad Copyright © 2017 S. Shukrullah et al. All rights reserved. Characterization of the Spindle Morphology Nanomicelles Assembled from Sericin and Gelatin Tue, 14 Nov 2017 07:24:11 +0000 Complex nanomicelles were prepared by sericin and type A gelatin with molecular weight of 5789 Da and 128664 Da separately. The assembling conditions were as follows: mass ratio (sericin/gelatin) was 1 : 1, protein concentration was 0.5%, temperature was 35°C, and assembling time was 18 hours. Scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and dynamic light scattering (DLS) were conducted to observe and characterize the complex nanomicelles. Results showed that the complex sericin/gelatin micelles was a kind of nanospindle micelles. The micelles had high electrochemical stability, thermal stability, antidilution stability, and storage stability. Xiaozhou Su, Lei Li, and Weihan Huang Copyright © 2017 Xiaozhou Su et al. All rights reserved. SnO2 Nanoparticles Decorated 2D Wavy Hierarchical Carbon Nanowalls with Enhanced Photoelectrochemical Performance Tue, 14 Nov 2017 00:00:00 +0000 Two-dimensional carbon nanowall (2D-CNW) structures were prepared by hot wire assisted plasma enhanced chemical vapor deposition (hw-PECVD) system on silicon substrates. Controlled variations in the film structure were observed with increase in applied rf power during deposition which has been established to increase the rate of dissociation of precursor gases. The structural changes resulted in the formation of wavy-like features on the 2D-CNW, thus further enhancing the surface area of the nanostructures. The FESEM results confirmed the morphology transformation and conclusively showed the evolution of the 2D-CNW novel structures while Raman results revealed increase in ratio indicating increase in the presence of disordered domains due to the presence of open edges on the 2D-CNW structures. Subsequently, the best 2D-CNW based on the morphology and structural properties was functionalized with tin oxide (SnO2) nanoparticles and used as a working electrode in a photoelectrochemical (PEC) measurement system. Intriguingly, the SnO2 functionalized 2D-CNW showed enhancement in both Mott-Schottky profiles and LSV properties which suggested that these hierarchical networks showed promising potential application as effective charge-trapping medium in PEC systems. Noor Hamizah Khanis, Richard Ritikos, Wee Siong Chiu, Choon Yian Haw, Nur Maisarah Abdul Rashid, Mei Yuen Chia, Poi Sim Khiew, and Saadah Abdul Rahman Copyright © 2017 Noor Hamizah Khanis et al. All rights reserved. Preparation of AuNPs/GQDs/SiO2 Composite and Its Catalytic Performance in Oxidation of Veratryl Alcohol Thu, 09 Nov 2017 06:44:46 +0000 Composites of gold nanoparticles and graphene quantum dots (AuNPs/GQDs) exhibit excellent dispersibility in aqueous solutions. Thus, it is difficult to separate them from wet reaction systems when they are used as catalysts. To resolve this issue, in this study, an AuNPs/GQDs composite was immobilized on silicon dioxide through the hydrothermal method, which involved the formation of an amide bond between the surface GQDs of the AuNPs/GQDs composite and the amino group of the silane. The as-synthesized AuNPs/GQDs/SiO2 composite was found to be suitable for use as a heterogeneous catalyst for the oxidation of veratryl alcohol in water and exhibited catalytic activity comparable to that of bare AuNPs/GQDs as well as better recyclability. Yaoyao Yang, Jiali Zhang, Fangwei Zhang, and Shouwu Guo Copyright © 2017 Yaoyao Yang et al. All rights reserved. Synthesis of Carbon Nanofibers with Maghemite via a Modified Sol-Gel Technique Thu, 09 Nov 2017 00:00:00 +0000 Carbon nanohybrid material (CNF/γ-Fe2O3) was obtained via a modified sol-gel technique consisting of two steps: functionalization of carbon nanofibers (CNF) in H2SO4/HNO3 followed by synthesis using Fe(NO3)39H2O. As a result, the iron content of the CNF/γ-Fe2O3 was increased by more than twice from about 40% to about 87% mass percent, compared to the pristine CNF and oxidized CNF specimens, as proved by energy dispersive X-ray fluorescence. Scanning electron microscopy images exhibited “cumulus” on the CNF/γ-Fe2O3 specimen surface, which showed the highest iron mass percentage, proved by energy dispersive X-ray spectroscopy. Transmission electron microscopy images confirmed attachment of γ-Fe2O3 cumulus to the inner and outer surfaces of the CNF walls after synthesis. The characteristic peaks of Fe 2p3/2 and Fe 2p1/2 appeared in the XPS spectra obtained on CNF/γ-Fe2O3. In addition, X-ray diffraction (XRD) results indicated formation of γ-Fe2O3 during the synthesis process. The Raman spectrum of the CNF/γ-Fe2O3 sample displays peaks with positions close to characteristic peaks of highly crystalline and monodisperse maghemite nanocrystallites. The synthesis of CNF/γ-Fe2O3 leads to an increase in the hydrophilicity of CNF and magnetic properties at room temperature. Nicolás Díaz Silva, Benjamín Valdez Salas, Nicola Nedev, Mario Curiel Alvarez, José M. Bastidas Rull, Roumen Zlatev, and Margarita Stoytcheva Copyright © 2017 Nicolás Díaz Silva et al. All rights reserved. Preparation and Characterization of Pd Modified TiO2 Nanofiber Catalyst for Carbon–Carbon Coupling Heck Reaction Thu, 09 Nov 2017 00:00:00 +0000 TiO2 fibers were prepared through electrospinning of poly methyl methacrylate (PMMA) and titanium isopropoxide (TIP) solution followed by calcination of fibers in air at 500°C. Cetyltrimethylammonium bromide (CTAB) protected palladium nanoparticles (Pd NPs) prepared through reduction method were successfully adsorbed on the TiO2 nanofibers (NF). Combined studies of X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) indicated that the synthesized Pd/TiO2 had anatase. BET indicated that the synthesized TiO2 and Pd/TiO2 had a surface area of 53.4 and 43.4 m2/g, respectively. The activity and selectivity of 1 mol% Pd/TiO2 in the Heck reaction have been investigated towards the Mizoroki-Heck carbon–carbon cross-coupling of bromobenzene (ArBr) and styrene. Temperature, time, solvent, and base were optimized and catalyst was recycled thrice. 1H NMR and 13C NMR indicated that stilbene, a known compound from literature, was obtained in various Heck reactions at temperatures between 100°C and 140°C but the recyclability was limited due to some palladium leaching and catalyst poisoning which probably arose from some residual carbon from the polymer. The catalyst was found to be highly active under air atmosphere with reaction temperatures up to 140°C. Optimized reaction condition resulted in 89.7% conversions with a TON of 1993.4 and TOF value of 332.2 hr−1. Leah O. Nyangasi, Dickson M. Andala, Charles O. Onindo, Jane C. Ngila, Banothile C. E. Makhubela, and Eric M. Ngigi Copyright © 2017 Leah O. Nyangasi et al. All rights reserved. Optical Design of Porous ZnO/TiO2 Films for Highly Transparent Glasses with Broadband Ultraviolet Protection Wed, 08 Nov 2017 07:34:34 +0000 We present a design of a bilayer porous film structure on a glass substrate for the highly efficient ultraviolet (UV) protection with high visible-light transparency. To effectively block UVB (280–315 nm) and UVA (315–400 nm), titanium dioxide (TiO2) and zinc oxide (ZnO) are used as absorbing layers having the appropriate coverages in different UV ranges with extinction coefficients, respectively. We show the process of refractive index (RI) matching by controlling porosity (). Effective RIs of porous media with TiO2 and ZnO were calculated based on volume averaging theory. Transmittances of the designed films with different effective RIs were calculated using rigorous coupled-wave analysis method. Using admittance loci method, the film thickness was optimized in center wavelengths from 450 to 550 nm. The results show that the optimal design provides high UV shielding performance at both UVA and UVB with high transparency in the visible range. We also analyze electrical field distributions in each layer and angle dependency with 3D HSV color map. Han Sung Song, Young Jin Yoo, Gil Ju Lee, Ki Soo Chang, and Young Min Song Copyright © 2017 Han Sung Song et al. All rights reserved. Effects of the Growth Time and the Thickness of the Buffer Layer on the Quality of the Carbon Nanotubes Tue, 07 Nov 2017 06:54:38 +0000 Direct growth of carbon nanotubes (CNTs) array onto silicon substrate by the chemical vapor deposition (CVD) is reported. Experimental results show that the thickness of the buffer layer has a significant effect on the morphology and defects of the array, and when the buffer layer is about 15 nm, the best array on the silicon substrate can be obtained. Moreover, when the growth time is less than the threshold time (70 minutes), the array height will increase with the increase of the time. Importantly, when the growth time is higher than this threshold time, the growth of array will stop, but when the growth is continuing, the amorphous carbon and carbon can cluster, which will affect the structure of the array. These results provide a good material basis for the device, thermal, and conductivity technology. J. Chuen Copyright © 2017 J. Chuen. All rights reserved. Tuning the Photoluminescence of Graphene Quantum Dots by Fluorination Tue, 07 Nov 2017 00:00:00 +0000 Fluorinated graphene quantum dots (F-GQDs) were prepared by mixing GQDs and XeF2 in a facile gaseous phase heating method. The F-GQDs with excellent water solubility have a F/C atomic ratio of 84.25% and a diameter of 2–6 nm. The photoluminescence (PL) properties of GQDs and F-GQDs were investigated systematically. The results showed that the PL emission of the F-GQDs exhibited an obvious blue-shift of 90 nm compared to that of the GQDs. Yi Luo, Yongjie Xu, Ming Li, Lang Sun, Guanghui Hu, Tao Tang, Jianfeng Wen, and Xinyu Li Copyright © 2017 Yi Luo et al. All rights reserved. Dose-Dependent Antimicrobial Activity of Silver Nanoparticles on Polycaprolactone Fibers against Gram-Positive and Gram-Negative Bacteria Mon, 06 Nov 2017 06:17:08 +0000 The adhesion ability and adaptability of bacteria, coupled with constant use of the same bactericides, have made the increase in the diversity of treatments against infections necessary. Nanotechnology has played an important role in the search for new ways to prevent and treat infections, including the use of metallic nanoparticles with antibacterial properties. In this study, we worked on the design of a composite of silver nanoparticles (AgNPS) embedded in poly-epsilon-caprolactone nanofibers and evaluated its antimicrobial properties against various Gram-positive and Gram-negative microorganisms associated with drug-resistant infections. Polycaprolactone-silver composites (PCL-AgNPs) were prepared in two steps. The first step consisted in the reduction in situ of Ag+ ions using N,N-dimethylformamide (DMF) in tetrahydrofuran (THF) solution, and the second step involved the simple addition of polycaprolactone before electrospinning process. Antibacterial activity of PCL-AgNPs nanofibers against E. coli, S. mutans, K. pneumoniae, S. aureus, P. aeruginosa, and B. subtilis was evaluated. Results showed sensibility of E. coli, K. pneumoniae, S. aureus, and P. aeruginosa, but not for B. subtilis and S. mutans. This antimicrobial activity of PCL-AgNPs showed significant positive correlations associated with the dose-dependent effect. The antibacterial property of the PCL/Ag nanofibers might have high potential medical applications in drug-resistant infections. Erick Pazos-Ortiz, Jose Hafid Roque-Ruiz, Efrén Amador Hinojos-Márquez, Juan López-Esparza, Alejandro Donohué-Cornejo, Juan Carlos Cuevas-González, León Francisco Espinosa-Cristóbal, and Simón Yobanny Reyes-López Copyright © 2017 Erick Pazos-Ortiz et al. All rights reserved.