Advanced Materials Research Vol. 704

Abstract: The effect of UV radiation and surface leakage current on the hydrophobic behavior of the RTV(room temperature vulcanized silicone rubber )silicone rubber was investigated. It's found that the ultraviolet radiation and surface leakage current both could weaken the hydrophobicity of the RTV surface in different degree.

Abstract: Cast aluminium alloy 354 has found widespread application in the automotive industry for its excellent mechanical properties and good castability. The stringent emission norms and demands for improved fuel economy have pushed automobile technology to new frontiers. This has led to efforts to reduce weight while maintaining higher vehicle performance. Cast aluminium alloy 354 is a material that performs with reasonable effectiveness in the high stress automobile environment. The present study looks at the use of strain energy density W and the quality index Q_o to determine the effect of process parameters like aging temperature and modification on the quality of the alloy 354 and also to monitor the effect of interrupted heat treatments T6I4 and T6I6 on the quality of the material. The strain energy density W calculated for the interrupted heat treatments on alloy 354 show a broad inverse relation with yield strength R_p. An improvement in the yield strength and the strain energy density of the alloy is observed when the alloy is subjected to modification. At artificial aging temperatures lower than the artificial aging temperature adopted in standard aging treatment an improvement in the Qo and W quality of the alloy 354 have been observed.

Abstract: In this paper, TiO₂ thin film with MSM (metal-semiconductor-metal) structure was used to fabricate ultraviolet (UV) detector. The film was fabricated via sol-gel method on silicon wafer with 300nm oxide layer and annealed at four different temperatures (400oC, 500oC, 600oC and 800oC). The quality of the thin films was characterized by means of X-ray diffraction and scanning electron microscope. Then a pair of symmetric Ag electrodes were deposited by thermal evaporation through a shade mask of interdigital structure. The photo-electric properties of the device including I-V characteristic, transfer characteristic and time response et.al. were studied with or without explored to 254nm UV light. The electrical measurements of the device show a big increase of current when explored the device to 254nm UV light, and the rise time of the device is very quick, but the fall time is relatively long. The detector with simple fabrication process, low cost, and superior performance would provide a potential application in UV detectors.

Abstract: Smoothness directly influences the color effect of printed matter, so it is very significant for researching the influence of paper smoothness on color effect of printed matter. This article researchs the relationships between the paper smoothness and the color effect of printed matter through experiments. The results show that, hue error of printed matter decreases with increased smoothness, color gamut of printed matter increases with increased smoothness, the glossiness of printed matter increases with increased smoothness, and color effect of printed matter better with increased smoothness. The results could provide a theoretical reference for papermaking enterprises to optimize the process of papermaking and produce suitable paper for color printing.

Abstract: Nanocrystalline nonferrous metals (Cu, Ag, and Al) were fabricated by room-temperature-molding method and vacuum-warm-compaction method, respectively. X-ray diffraction, Positron annihilation spectroscopy, and density test were utilized to characterize these as-prepared nanocrystalline specimens. The thermal stability and micro-void distribution of the as-prepared nanocrystalline metals were compared and discussed in detail. The experimental results show that the increasing of density is unremarkable while the microstrain reduces during warm-compaction process. The nanocrystalline nonferrous metals prepared by VWC have better thermal stability. Positron annihilation spectroscopy analysis indicates that, compared with the specimens prepared by RM, the average size of micro-void and proportion of single vacancy is a little larger in nanocrystalline copper fabricated by VWC.

Abstract: Poly (3-hexylthiophene) (P3HT) was synthesized via chemical oxidative reaction at room temperature with anhydrous ferric chloride as oxidant. The hybrid films of P3HT were prepared by doping inorganic semiconductor nanoparticles of CdS. Fourier transform infrared (FT-IR) spectrum, UV-vis, fluorescence and resonance light scattering (RLS) spectra were applied to characterize the photophysical properties of P3HT and doped polymer. The results indicated that the infrared absorbance of hybrid films increased with the increase of doped CdS content. The intensity of UV absorption presented a slight increase, the blend spectra were simply the sum of the absorptions of the constituent parts of the composite solution. With the addition of CdS nanoparticles, the emission peak of P3HT was shifted to longer wavelengths. The shift from 543 to 567 nm was due to the fluorescence resonance energy transfer between CdS nanoparticles and P3HT, and then the red-shift from 567 to 573 nm was caused by the agglomeration of CdS nanoparticles. RLS spectra revealed that the maximum scattering wavelength of systems initially showed a blue-shift, and then exhibited a pronounced red-shift with the addition of CdS nanoparticles. These findings provided insights into the role of spectroscopic techniques in studying the photophysical properties of composites. Our further work is toward investigating the mechanism and dynamic process of exciton interaction between polymers and inorganic semiconductor nanoparticles.

Abstract: Polycarbonate has been widely used in optical and aeronautic areas due to its low weight, transparency and high impact strength. The deposition of hard, transparent and scratch-resistant coatings on polycarbonate can significantly improve the surface mechanical behavior while capitalizing on their desirable bulk characteristics. In this work, nanomechanical properties of transparent scratch-resistant coating on polycarbonate, including nanoindentation and nanoscratch behaviors, were detailed investigated. The significant enhancement of nanomechanical response, containing hardness elastic modulus and friction-resistance, could be obtained after the deposition of the scratch-resistant coating. The results of the systematic investigation of indentation and scratch performance at the nanoscale reveal their significant differences between the surface region and bulk of coatings. Furthermore, the aging properties of scratch-resistant coatings under hygrothermal environment (65°C water for different time) can be followed-up and quantitatively detected in terms of hardness and maximum loading depth changing by nanoindentation technique, which prove to be a new and available method to study aging behavior of thin coatings.

Abstract: As a promising two-dimensional nanomaterial with outstanding electronic, optical, thermal, and mechanical properties, graphene has been investigated for many applications. In this work, we present a facile route for the integration of graphene with light-sensitive copper oxides for optoelectronic applications. Graphene synthesized by a solvothermal process is found to be a robust substrate on which photoconductive Cu_xO with a particle size of about 50 nm can be deposited by a simple method. The morphology of graphene and graphene-Cu_xO is characterized by SEM and TEM. Photoluminescence measurements are also conducted, and the results show that the excited fluorophore in the P3HT backbone is effectively quenched by the electronic interactions at P3HT/graphene interfaces; however, the incorporation of Cu_xO increases the excited fluorophore. Photoelectrical experiments show that clean, cheap and easily prepared Cu_xO/graphene has much stronger photo-induced electrical current compared with graphene, thus suggesting a promising candidate for organic photovoltaic applications.

Abstract: Poly[bis(trifluoroethoxy)phosphazene] (PBFP) can be prepared via thermal ring-opening polymerization (ROP) of hexachlorotriphosphazene ((PNCl2)3) or ambient temperature cationic living polymerization (ALP) of monomeric Cl3P=NSiMe3, followed by introduction of OCH2CF3 groups via standard salt metathesis protocols. The resultant polymer morphology is dependent upon synthetic methodology, processing method (e.g. solvent casting, heat cycling, etc.) and the presence of inorganic nanoparticles, which were found to inhibit crystallization. 1H, 19F and 31P solid-state NMR spectroscopy was employed to investigate crystallization in solvent cast and heat-treated samples of pure PBFP and composites of nano-crystalline TiO2 doped PBFP.

Abstract: Nanocrystalline tin phosphide Sn₄P₃ was synthesized from red phosphorus and tin chloride SnCl₂2H₂O by a low temperature (200°C) solvothermal reaction in ethanolamine for only 10 hours. The important parameters of solvothermal processmolar ratio of initial components (P/Sn), temperature and duration were investigated. The phase, composition and morphology of the products were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The ideal solvothermal conditions to synthesize pure and nanocrystallined Sn4P3 were summarized in this work.