Advanced Materials Research Vols. 93-94

Abstract: Intrinsic and extrinsic semiconductor nanocrystals seem to be good candidates for modern era optoelectronic and photo-catalytic applications due to their size tunable photo-physical and photo-chemical properties. In the present investigation, polyvinyl pyrrolidone (PVP) capped quencher impurity (Ni) doped ZnS nanocrystals have been synthesized using facile bottom-up synthesis technique; colloidal chemical co-precipitation method. Crystallographic and morphological characterization of synthesized nanomaterials have been carried out using X-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. Photo-catalytic activity of the synthesized nanomaterials has been studied using methylene blue (MB) dye as a test contaminant. Photo-catalytic behavior dependence on dopant concentration, UV radiation curing and annealing of synthesized semiconductor nanomaterials have been studied in detail under sun light exposure.

Abstract: Attempt to improve latex immunoagglutination assay, a rapid method in medical diagnostics, reporting as quantitative results was interested in this study by using microfluidic device. Sensitized latex was produced by physical adsorption of human polyclonal IgG antibody to Plasmodium falciparum malaria parasite onto carboxylated polystyrene particle. Conventional latex agglutination assay was firstly performed to verify specific interaction of antibody on the bead surface versus antigen in malaria plasma. The agglutinate size around 30 µm was observed under optical microscope. The proportion of the plasma and the particle was optimized, and an appropriate ratio was applied in microfluidic device. Three patterns of the device were used with the agglutinate size comparison after 10 min as followed: rapid mixing > U-shaped loop > straight capillary Y-junction patterns. However, compared with patient plasma, small agglutinates were also observed when using normal serum.

Abstract: Precious metal nanoparticles (e.g. Au, Pd and Pt) on activated carbon cloths (ACCs) were simply prepared by impregnation of metal salts dissolving in ethanol solution. Pretreatment of the ACCs was firstly performed in hydrochloric acid solution and nitric acid as oxidizing agent was employed in order to introduce oxygen complex on the ACCs fiber surfaces. Uniformly dispersed metal nanoparticles with diameter of 5-20 nm on the ACC surfaces were simply achieved without using reducing agents. Morphology and composition of the metal adsorbed ACCs were examined by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), respectively. Electrolytic activity of metal/ACCs was investigated by using cyclic voltammetry (CV) to demonstrate the electron-transfer properties. Results demonstrate that metals adsorbed ACCs were easily prepared with simple procedures which will be more convenient for preparations and applications.

Abstract: To achieve a proper dispersion of nano-particles polymer matrix and to yield a better compatibility between the nano-particles and polymeric material, the use of different coupling agents for surface modification of nano-particle is recommended. In this research, surface of TiO2 was modified by hydrolytic condensation of titanium isopropoxide with three different silane coupling agents, hexadecyl trimethoxysilane (HTMS), triethoxyvinylsilane (TEVS) and aminopropyl trimethoxysilane (APS). The grafting of silane coupling agents on the TiO2 nano-particles surface was characterized using TGA and FTIR techniques. Mechanical properties of polyethylene composite films were evaluated via tensile strength measurement. Surface morphology of the particle was studied by SEM and TEM. The result showed that surface treatment TiO2 nano-particles with TEVS could improve dispersibility of TiO2 and showed the optimum mechanical properties.

Abstract: A polymer fabricated by mixing PU soft segment and epoxy bore the thermal characteristics of the melting temperature, Tm, of PU soft segment and the glass transition temperature, Tg, of epoxy. The polymer fabricated even exhibited the shape memory effect at the Tg and Tm. Based on this observation, it was speculated that simply mixing two polymers bearing totally different thermal characteristics each other could result in a two-stage SMP, which could exhibit the shape memory effect at the two distinct temperatures. However, it was actually observed that the two-stage SMP was not always successfully created by that method. But DSC measurements revealed that such an unsuccessfully fabricated SMP still bore the thermal characteristics of its ingredient polymers. Hence, the mixing of appropriate polymers still could result in a new two-stage SMP, and the method of two-polymer-mixing must be still an effective method for creating a two-stage SMP.

Abstract: In this work, soda-lime-silica glass has been selected for coloring as base glass. The glass composition in mol% is (65-x) SiO2: 25Na2O: 10CaO: x Fe2O3, where x is 0.00, 0.02, 0.05, 0.10, 0.30, and 0.50. Optical absorption and electrons spin resonance spectroscopy were conducted for five different doping rates. The optical spectra of Fe2O3 doped glasses show three absorption bands at 380, 420 and 435 nm. These peaks correspond to Fe3+ ions. The ESR spectra of all glasses doped with Fe2O3, they show three strong ESR absorption peaks at the g = 2.0050.003, 4.2910.008 and 7.1240.008. The intensity of these peaks is increased when the Fe2O3 concentration is increased.

Abstract: CuO nanostructures were synthesized by thermal evaporation method. Using Cu metal plate at temperature of 400oC for 24 hrs in one atmosphere of oxygen and studied structural and gas sensing properties. The CuO nanostructured were investigated by the stereo microscope (image analyzer), X-ray diffraction, scanning electron microscope. The diameter of CuO nanowires vary from 10 nm to 50 nm and length of several 10 micrometers. The sensitivity of CuO nanostructures and response were performed at room temperature for ethanol and CO2 sensor.

Abstract: Titanium dioxide powder was synthesized by an oxalate co-precipitation method with titanium isopropoxide and oxalic acid as the starting precursors. White precipitate was obtained after adding ammonium hydroxide until the final pH of solution was 8 and then calcined at 400-800 °C for 2h. The phase was characterized by X-ray diffraction. Single phase anatase structure was obtained after calcination at 400 °C. Multi-phase of anatase and rutile structure was obtained after calcined at 600 and 800 °C. The morphology was investigated by scanning electron microscopy. The particle was irregular in shape and highly agglomerate with a range of particle size from 0.1-0.3 µm. The photocatalytic destruction of methyl orange by titanium dioxide was determined by Ultraviolet spectrophotometry. Titanium dioxide powder synthesized by an oxalate co-precipitation method after calcination at 800 °C showed the highest photocatalytic activity.

Abstract: To make significant progress in the fight against cancer, treatment should target cells more specifically, produce fewer side effects, be easy to administer and deter tumor viability on multiple levels. We have attained dramatic in vivo tumor shrinkage and tumor vasculature disruption using a ternary biomolecular nanoparticle comprised of polymeric carrier polysaccharide heparin, anticancer drug retinoid and targeting ligand folic acid. The conjugation of retinoid and folic acid to heparin enhanced the water solubility of the drug, enabled selective targeting, and enhanced the role of heparin as anti-cancer drug carrier by eluding the coagulation cascade. This approach for targeting tumor holds great promise for treatment of various types of cancer. The folic acid linked heparin-retinoid conjugates (HFR) reactions was conjugated with ester and amide bonding which was confirmed by fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H-NMR). The ratio of HFR conjugates was measured with Ultra-Violet spectrometry (UV-spectrometry). The particle size of HFR nanoparticles was measured by dynamic light scattering (DLS), and transmission electron microscopy (TEM). HFR conjugates were spherical and showed a diameter range of 200-300 nm in size. The nanoparticles maintained their stability in serum condition for 48hrs and have the high potential for applications in biomedical field.

Abstract: The property of cellulose microfibril reinforced natural rubber film was studied. Cellulose microfibril was prepared from banana powder (300 µm). The interconnected structure of cellulose microfibril having a diameter of 27 nm was observed by TEM. The effect of cellulose microfibril content (0.8-3.2 % wt) in the property of NR nanocomposite film was studied. Tear strength and thermal properties of the NR nanocomposite film is improved by increasing the cellulose microfibril content. Moreover, water absorption of the nanocomposite film is increased by increasing cellulose microfibril content. Increasing of cellulose microfibril content also enhances water permeation of nanocomposite films.