Advanced Materials Research Vol. 1024

Abstract: Normal 0 false false false EN-US X-NONE AR-SA /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";}Nanocrystalline cupric oxide (CuO) film was prepared by sputtering of pure copper metal on n-type single crystalline Si substrate under argon-oxygen ambient. Structural and morphological analyses of the as-deposited CuO films were performed by X-ray diffraction (XRD) diffractometer and Field Emission Scanning Electron Microscopy (FESEM). The results show Single crystalline granular nanocrystalline (002) CuO films, with 18 nm crystallite size. Current-voltage (I-V) and capacitance-voltage (C-V) measurements were performed for p-CuO/n-Si hetrojunction. Diode parameters such as saturation current (I_s=9.5E-6 A) and ideality factor (n=1.86) were extracted from the dark I-V characteristics. Potential barrier height of the junction (ϕ_i=1.1V) was revealed from (1/C²- V) plot. Normal 0 false false false EN-US X-NONE AR-SA /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";}

Abstract: Colloidal gold (Au) nanoparticles (NPs) deposition on silicon (Si) substrate is highly affected by the deposition technique and surface properties of the substrate. Spin-coating technique has been proven to be an efficient approach in terms of cost, time and maintaining the quality of the deposition. However, to prevent the agglomeration of NPs and obtain desirable density and distribution of NPs on the substrate, precise control of the spin-coating parameters is required. In this study colloidal Au NPs were spin-coated onto a modified, yet linker-free Si surface. By controlling the spinning speed, acceleration, dwelling time, and the volume of NPs colloidal solution, the density and distribution of the NPs on Si were optimized. Scanning electron microscope was used to investigate the NPs density in each step of the process. Results showed that the distribution of NPs on Si substrate is highly dependent on the spinning speed, duration, and acceleration rate as well as surface properties of Si substrate.

Abstract: Nanoporous anodic WO₃ was annealed at three different times of 1h, 2h, and 3h at a constant temperature of 500oC. This was to investigate the intercalation and deintercalation behaviour of Li⁺ in this annealed nanoporous oxide. The as-anodised WO₃ is amorphous and after annealing, monoclinic WO₃ was observed with much higher degree of crystallinity when the time of annealing was increased from 1h to 3h. By electrodiffusion of Li⁺ in the nanoporous structure, an ion exchange between fully oxidized states (W⁶⁺) which is the octahedral coordination dominates (WO₆) and Li⁺ could happen. This causes changing of the colour of the yellowish WO₃ to bluish WO₃.Li₂O. This work showed the effect of annealing time on intercalation of Li⁺ ion with WO₃, however crystallinity can play a good role for electron movement, it cause a decrease in Li⁺ ion interaction with WO₃.

Abstract: Cerium oxide (CeO₂) or known as ceria were deposited on titanium dioxide, TiO₂, nanotubes by electrodeposition process as to produce hybrid materials that can generate photocurrent. The electrodeposition process is done by using 0.1 M cerium chloride mixed with 0.1 M ammonium acetate as ligands to promote stability complexes in a standard two electrode bath. Voltage and pH were controlled to ensure the most optimum condition of cerium oxide deposition. Samples were then annealed at different temperatures. Photocurrent results indicate that annealed sample at 450°C shows the best photocurrent due to high degree of anatase and cubic crystallinity.

Abstract: Graphene nanoplatelets (xGnP) were investigated as a novel nanoreinforcement filler in poly (lactic acid)(PLA)/poly (ethylene glycol)(PEG) blends by melt blending method. The prepared nanocomposites exhibited a significant improvement in tensile properties at a low xGnP loading. The tensile properties demonstrated the addition of 0.3wt% of xGnP led to an increase of up to 32.7%, 69.5% and 21.9% in tensile strength, tensile modulus and elongation at break of the nanocomposites respectively, compared to PLA/PEG blend. The nanocomposites also shows enhanced thermal stability compared with PLA/PEG blend in thermogravimetry analysis (TGA). Scanning electron microscopy (SEM) image of PLA/PEG/0.3wt% xGnP displays good uniformity and more homogenous morphology.

Abstract: Graphene nanoplatelets (GNP)/epoxy and multi-walled carbon nanotube (MWCNTs)/epoxy thin film composites were fabricate by ultrasonication and spin coating technique. The tensile properties of epoxy containing (0.2, 0.6 and 1 vol%) of GNP sonicated at different duration (10, 20 and 30 min) or MWCNTs sonicated at 20 min only have been studied. It was found that the addition of GNP was decrease the tensile strength and modulus. However, among all samples, GNP/epoxy produced by 20 min sonication time showed slightly higher tensile strength and modulus. The effect of sonication time was supported by morphological analysis, which showed an improvement of GNP dispersion with increased sonication time. However, GNP deformation was observed with long sonication time. Compared with MWCNTs/epoxy sonicated at 20 min at different filler loadings, GNP/epoxy shows lower tensile properties. This can attribute to the two dimensional GNP are more easier to aggregate than MWCNTs.

Abstract: In this study, mechanical characteristic of flexible polymer membrane embedded with nanomagnetic particles is analyzed using COMSOL Multiphysics 4.3. The mechanical properties of the membrane is studied by considering the magnetic particles as matrix structures embedded inside the polymer. The target of this work is to realize a new type of magnetic actuator that is able to generate a strong magnetic field and has large mechanical deformation capability as well. On the other hand, the flexible membrane properties should be optically paternable and display very high magnetic sensitivity. Therefore the study is focused not only to analyze the membrane properties but also the technique to fabricate the membrane for MEMS actuator. In this work, the magnetic force acting on the membrane, the length and height of the membrane, and the total volume of Ni particles were set to be constant. A good agreement between simulation and calculation on maximum membrane deformation without particle content was observed. It is shown that by having Ni particles embedded in polymer membrane, the deformation capability was greatly increased up to 30.9 μm. Therefore this study has proven that the smaller size of the magnetic particles with the planar structure arrangement and homogenous distribution of embedded particles can enhance larger membrane deformation. The fabrication concept of the membrane and material synthesis are also introduced. The results obtained in this study will have an important role in the development of electromagnetic actuator for fluids injector integrated in Lab-on-Chip system.

Abstract: The reaction of EMCs with the triphenylphosphine-1,4-benzoquinone (TPP-BQ) latent catalyst also had a higher temperature sensitivity compared to the reaction of EMCs with triphenylphosphine (TPP) catalyst. In resin transfer molding, EMCs containing the TPP-BQ thermal latency accelerator are least active at a low temperature. Consequently, EMCs have a low melt viscosity before gelation, and the resins and filler are evenly mixed in the kneading process. Additionally, the rheological property, flowability, is increased before the EMC form a network structure in the molding process. The proposed kinetic model adequately describes curing behavior in EMCs cured with two different organophosphine catalysts up to the rubber state in the progress of curing.

Abstract: Glass fibres with multi-functional properties were developed by using i) Polymer-based nanocomposites containing epoxy, carbon nanotubes and graphene, and ii) Titanium dioxide nanoparticles. The mechanical, electrical, barrier and photocatalytic performance of fibres were studied. Raman and electrical responses of fibres under mechanical load were coupled for in situ sensing of deformation in composite structure. The low cost and excellent flexibility of glass fibres make them ideal materials as supporter to deposit photocatalytic nanoparticles for the removal of organic pollutants in water.

Abstract: The use of reclaimed and devulcanised material in virgin rubber compounds has attracted the attention of many rubber industries due to increasing raw material costs, diminishing resources and growing awareness of environmental issues. Several methods have been developed to reclaim rubber waste, for example, thermo-and chemo-mechanical processes, microwave regeneration, microbial action and ultrasonic regeneration. However, extensive research on processes for high-quality recycling materials based on waste tyres is still lacking. In this study, optimised processing conditions for the devulcanisation of whole passenger car tyres using diphenyldisulphide (DPDS) as a devulcanisation aid will be applied. The devulcanised ground tyre rubber (D-GTR) obtained from the process was blended on top of the original tyre tread formulation at different concentrations. The results so far indicate that the addition of D-GTR influences the properties of the blend, but to a lesser extent than the commercially used powder or reclaim types do, for which loadings less than 5% can be applied. The main reason for the influence of D-GTR on the rubber properties is inhomogeneities in the D-GTR/virgin rubber blend and quality aspects of raw GTR.