Laser-induced birefringence of methyl red in a polymeric nanocomposite prepared by sol–gel method

Non-linear optical (NLO) dyes used as guests in polymeric films have recently attracted interests in optical applications. In this regard, dye-grafted polymeric systems can outperform conventional guest?Chost dye-containing films because they have lower loading limitations and aggregation problems. These give rise to enhanced molecular orientation. The work presented here is an attempt to study the laser-induced birefringence for a novel sol?Cgel based polymeric nanocomposite prepared by reacting an NLO dye (methyl red) and an epoxy silane coupling agent at different concentrations of dye. 3-Glycidoxy propyltrimethoxysilane was hydrolyzed and condensed to prepare a siloxane structure from which a dye-containing hybrid was obtained. The structural and morphological properties of the resulting nanocomposites were studied by FTIR spectroscopy, differential scanning calorimetry and transmission electron microscopy. Results showed that the dye was chemically attached to the siloxane structure built through sol?Cgel processing. This chemical modification leads to nanostructured morphology in which inorganic phase was entangled to the organic phase. The size of clusters formed was 60?C80?nm in dimension. The optical responses of nanocomposites were investigated at different process parameters, including dye concentration, film thickness and curing regimes. These were then discussed based on the photochemical and photothermal properties of the dye molecules, the rotation dynamic of which was shown to strongly depend on the physical and chemical properties of the host. The samples with 8 wt% of dye revealed the maximum birefringence, while the sample with 10 wt% showed the best memory effect. The best condition for curing was found to be 24?h. By increasing the film thickness, there was an increase in the amount of induced birefringence.     

Monodispersed mesoporous silica nanospheres based on pyridinium ionic liquids

In the past decades, ionic liquids (ILs) have garnered a lot of attention especially in the field of green chemistry due to their unique properties which help to solve the problems posed by organic solvents. Interestingly, their applications are not limited to that only as ILs have the potential to become alternative templates in the development of mesoporous silica nanoparticles (MSNs). This work reported the usage of a series of pyridinium ILs as template in the synthesis of monodispersed mesoporous silica nanosphere (MNSs) via two methods. Both syntheses utilize triethanolamine (TEA) as the base catalyst where in one method the TEA undergoes pre-treatment process while the other did not. Besides that, the effects of pyridinium ILs alkyl chain length were also investigated. MNSs generated via both methods exhibit spherical morphology and decreasing average particles size with increasing alkyl chain length of pyridinium ILs. The MNSs porosity were further analyzed through nitrogen sorption analysis where the surface area were in between 71.85 and 525.02 m² g^?1 and the pore volume was up to 1 cm³ g^?1.     

Sulfur dioxide removal by calcium-modified fibrous KCC-1 mesoporous silica: kinetics,thermodynamics, isotherm and mass transfer mechanism

Journal of Porous Materials - The removal of sulfur dioxide from industrial flue gas through dry flue gas desulfurization method commonly involves the use of adsorption process with porous sorbent....     

Hierarchical bioceramic scaffold for tissue engineering: A review

Bioceramic scaffolds have a promising application in bone-tissue engineering field. However, bioceramic scaffolds exhibit low fracture toughness; hence, to overcome this problem, hierarchical bioceramic scaffold or bioceramic scaffolds coated with polymer are produced. Starting with the fundamental requirements for bioceramic scaffold, this article provides detailed information on recent developments of method to produce porous bioceramics scaffold and hierarchical bioceramic scaffold. Chemical modifications to enhance interfacial adhesion and formation of interpenetrating network structures between the bioceramic scaffold and the natural polymer layer are discussed in this article. Areas of future research are highlighted at the end of this review.