Advanced Materials Research Vol. 662

Abstract: Covalently tethered well-defined new three-arm star hydrophilic poly(ethylene glycol) monomethacrylate (PEGMA) brushed nanoparticles on silicon surface have been successfully prepared by (i) synthesis a novel type of three-arm star-shaped preceding initiator, trifunctional hydroxy-based N-allyl-3,4,5-trihydroxybenzamide (NATHB), (ii) UV-induced hydrosilylation of NATHB with the hydrogen-termined Si(100) (Si-NATHB surface), (iii) coupling of 2-bromo isobutyrl bromide with the hydroxyl of NATHB by the esterification to provide the initiators (Si–NATHB–R3Br) for the subsequent ATRP, (iv) surface-initiated ATRP of PEGMA and 2-hydroxyethl methacrylate monomethacrylate (HEMA) to give the linear Si–NATHB–g–P(PEGMA) brushes and the Si–NATHB–g–P(HEMA) surface, (v) further coupling of 2-bromo isobutyrl bromide with the hydroxyl of P(HEMA) by the esterification to produce the macroinitiators (Si–NATHB–g–P(HEMA)-R3Br) and (vi) surface-initiated ATRP of PEGMA to give the comb-shaped Si–NATHB–g–P(HEMA)–g–P(PEGMA) brushes surface. Kinetics study indicated that the chain growth of P(PEGMA) and P(HEMA) from the functionalized silicon surfaces was consistent with a “controlled” or “living” process. The chemical composition and functionality of the silicon surface were tailored by the well-defined star linear and comb-shaped P(PEGMA) brushes, which provide with this type of surface structures formed in three brushes under conditions of spatial constraints imposed by their chemical connection to a single grafting site. XPS spectra testify that the linear and comb-shaped P(PEGMA) have been grafted on the Si-NATHB surface. AFM imaging of the hydrophilic polymer brushed nanoparticles imaged distinctive morphology when they were prepared into linear and comb-shaped brushes structure.

Abstract: Preferred orientation GaN films are deposited on freestanding thick diamond films by electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition (ECR-PEMOCVD). The TMGa and N2 are applied as precursors and different N2 flux is used to achieve high quality GaN films. The influence of N2 flux on the properties of GaN films is systematically investigated by x-ray diffraction analysis (XRD), atomic force microscopy (AFM), electron probe microanalysis (EPMA) and Hall Effect Measurement (HL). The results show that the high quality GaN films deposited at the proper N2 flux display a fine structural and electrical property and the Ga/N atomic ratio plays an important role in the electrical property of GaN films.

Abstract: In this study, analytical solutions are obtained by homotopy perturbation method (HPM) for the nonlinear vibration equation of single-wall nanotube (SWNT). Novel and accurate analytical solutions for the frequency and displacement are derived. Comparison of the result obtained by the HPM with exact solutions reveals that only the first or second order approximation of the HPM leads to higher accurate solution.

Abstract: Quartz Fibre/nano-Hydroxyapatite/Polyamide 66(QF/n-HA/PA66) composite was prepared by extrusion molding method. The QF is well dispersed in the nano-hydroxyapatite/polyamide 66 matrix and some interaction and new interface formed between QF and n-HA/PA66. Tensile strength, compressive strength and flexural strength of the 38wt%QF/n-HA/PA66 composite reached 81 MPa, 190 MPa and 195 MPa, which were higher than those of human cortical bone. Mechinical properties were improved with the increasing of QF content and QF well enhanced biomechanical properties of the composite. Based on the excellent biomechanical properties of composites, the long load-bearing thigh bone substitute was fabricated for tumour infected thigh bone patient.

Abstract: MnO2 nano-materials can remarkably catalyze the electrochemical reduction reaction of O2, so MnO2 nano-materials can be used as catalysts for electrogenerated chemiluminescence (ECL) of Ru(bpy)32+ in this paper. As a result, a novel cathodic ECL of Ru(bpy)32+ at positive potential of +0.4 V (vs. Ag/AgCl) was triggered by reactive oxygen species (HO2•- or OH•-) on an in situ electrodeposited MnO2 nano-structured electrode. Finally, catalytic mechanism of MnO2 nano-materials is deduced and provides a theoretical basis for preparing novel ECL Sensor with high sensitivity.

Abstract: Al-doped zinc oxide (ZAO);nanorod arrays;thin film;preparation; photoluminescence. Abstract: ZAO thin films were deposited on glass substrates by sol-gel method and then by controlling processing parameters such as the amount of doped Al and stability, etc.well-aligned Al-doped ZnO nanorod arrays with a narrow diameter distribution were successfully grown on substrates by hydrothermal method, where the substrates were spin-coated with seed layer.The experiments show the 2% Al-doped and diameter about 50nm of ZAO nanorod arrays has the best photoluminescence and surfactants can promote the growth of ZAO rod-like nano-structures and contribute to the formation of ZAO nanorod arrays with highly oriented nanorod arrays.

Abstract: Hierarchical ZrO2 nanorods have recently received considerable attention due to their special physical and chemical properties. However, traditional preparation methods are involved in expensive equipment, complicated process and high production cost. Here we report a simple hydrothermal approach to prepare hierarchical ZrO2 nanorod. The results show that as-synthesized products are composed of many nanorods with 80~150 nm in diameter and 15~20 μm in length. After annealing, the final product was involved into hierarchical monoclinic ZrO2 (m-ZrO2) nanorods, namely, the big nanorod was made up of many small nanorods with 20~30 nm in diameter and 300~500 nm in length. The possible formation mechanism was proposed based on a series of chemical reactions and the natural properties of zirconium.

Abstract: In the present study, we demonstrated an effective cost and environmentally benign method to synthesize the silver nanoparticles (AgNPs) using aquatic weed namely water hyacinth as a reducing agent. Ultraviolet irradiation was also combined in the process to enhance the reaction rate. The aqueous silver ions mixed with water hyacinth leaf extract under UV irradiation were reduced to AgNPs. The mixture color was changed from light yellow to yellowish-brown color within 5 min due to excitation of surface plasmon vibrations in AgNPs. The formation of AgNPs was confirmed by UV-visible spectroscopy, X-ray diffraction (XRD) spectrometry, energy dispersive X-ray (EDX) analysis and transmission electron microscopy (TEM). The AgNPs were found to be polycrystalline in nature and spherical particles with mean diameter of 12.54 ± 0.19 nm. The XRD pattern peaked at different diffraction angles corresponding to the (111), (200), (220), and (311) planes indicated that AgNPs have face-centered cubic (fcc) unit cell structure. This proposed method revealed that unwanted plant can utilize in nano-manufacturing as well.

Abstract: MnO2 nanowires with large aspect ratio were successfully synthesized via a hydrothermal method. In this method, Mn(NO3)2 was as a source of manganese and NH4NO3 as an oxidant. The structure and morphology of the MnO2 nanowires were characterized by X ray diffraction (XRD) and scanning electron microscope (SEM). Their lateral elastic modulus was characterized via a nanoscale three-point bending test by atomic force microscopy (AFM) equipped with picoforce. The results indicate that the crystal form of MnO2 was β-MnO2. The elastic modulus of the nanowires decreased with the increase in nanowire diameter. This elastic modulus was in the range of 33.36-77.84GPa as the diameter ranged from 240 to 185nm.

Abstract: This paper develops one method to characterize nano dimension standards using Scanning White Light Interference Sensor (SWLIS) based on Nano Measurement Machine (NMM). The experimental results show the average value of SHS8-440 low step height standard is 44.15 nm and SHS8-100.0 high step height standard is 100.29 μm, with a standard deviation of 0.30 nm and 0.03 μm, respectively. Also, SWLIS is performed to measure and characterize step height standards, which cover most of the conventional step height standards produced by VLSI Standards Incorporated (VLSI). Additionally, atomic force microscope (AFM) is used as a beneficial supplement due to low lateral resolution of optical methods. The average value of TGZ1_PTB 1D grating from NT-MDT Company is 3000.2 nm with a standard deviation of 0.3 nm by AFM.