Refractive Index Border Associated with Nonlinear Optical Properties in Superhybrid Transparent TiO2 Nanoparticles-Polymer: Great Potential for Ultrafast Optical Waveguide in Optical Communication

The excellency of a superhybrid material based TiO2 nanoparticles (NPs) has been improved by the surface modification of the TiO2 with a coupling agent of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane to render them highly compatible with organic monomer mixtures avoiding aggregation. Such TiO2 NPs are then attached with a polymer. The border of linear refractive index of hybrid TiO2 NPs-polymer is enhanced in comparison with that of pure epoxy resin or polymer. Nonlinear refractive index and nonlinear absorption coefficient of hybrid TiO2 NPs-polymer are measured by femtosecond Z-scan technique at 800 nm. This hybrid material has been fabricated and studied to have a great potential for ultrafast optical waveguide in optical communication quantified by the propagation loss of the hybrid TiO2 NPs-polymer optical waveguide in the range of 4.79 to 11.90 dB/cm, which is depending on the volume percent of TiO2 NPs

Radial Distribution Function Analysis of the Polyamide Thin Film Composite formation using Trimesoyl Chloride and Piperazine

Polyamide thin film composite (TFC) membranes are well known for their performance and strength which normally applied in pervaporation dehydration and reverse osmosis field. TFC is produced by the rapid reaction between aqueous and organic monomer. However, the interaction between monomers is not well discussed at the atomic level and there is no precise tool to measure the effectiveness of the selection of organic with the aqueous monomer to form a stable TFC layer. Thus, this paper aims to analyze the interaction between aqueous monomer and organic monomer using the Molecular Dynamic (MD) simulation to form the TFC membrane. This work was done by using Piperazine (PIP) as the aqueous monomer with the combination of Trimesoyl Chloride (TMC) as the organic monomer in the binary systems. The simulation involved the setting of Ewald Summation Method, COMPASS force field, equilibrium phase by microcanonical, NVE (constant volumes and total energy) and run-production stage by NPT (constant pressure and temperature). Analysis by the Radial distribution function (RDF) explicates the intermolecular interfacial of 5.75 Å between the bonding of N (Amine) - C (TMC) atoms at the distance of 1.0 Å. This study suggested that the TFC formed by the interaction between TMC - PIP is very much stable based on the higher interaction in a very short distance.

Preparation of Alumina Powders through Pyrocatechol, Resorcinol Mediated Sol-Gel Method

Ultrafine alumina powders were synthesized through pyrocatechol and resorcinol mediated sol-gel process. Aluminum nitrate was applied as the Al source and PVP was the dispersant. X-ray diffraction (XRD) study displayed that γ-Al2O3 powders formed in the range of 800-900 °C, and then γ-Al2O3 transformed to α-Al2O3 at higher temperatures, pure α-Al2O3 powders could be obtained at 1000 °C by using resorcinol as organic monomer. The results of transmission electron microscopy (TEM) revealed that Al2O3 nanoparticles with γ crystalline phase had grain sizes in the range of 5-40 nm. Scanning electron microscopy (SEM) observation displayed that the morphology of the prepared α-Al2O3 powders had aggregated bodies formed by Al2O3 grains in the range of 0.2-0.5μm. These results provide a new way of preparation of alumina powders.