This article provides a brief overview of liquid-liquid phase separation fundamentals. First we discuss thermodynamic factors that drive spontaneous phase separation from homogeneous binary liquid mixtures. Next we introduce some mathematical models for chemical potentials in non-equilibrium state and intermolecular frictions to derive the governing equation for phase separations. Following classical Cahn-Hilliard theory, we show how the linear stability analysis gives the critical wavelength, at which the growth rate of concentration fluctuation shows a maximum. Finally, we discuss possibilities to utilize phase separation structures as a template to assemble/deposit/stratify solid particles on a solid surface.
Wavelength conversion materials with high thermal conductivity and heat resistance have been strongly desired for high power semiconductor lighting source. Glass has higher heat resistances at elevated temperatures than resin and dispersion of high thermal conductive particles should result in the improvement of thermal conductivity of the composites. In this study, the composites of phosphate glass dispersing nitride phosphor and high thermal conductive particles were fabricated instead of typical composites of resins and oxide phosphors. As a result of verification of reactivity of the nitride phosphor and the high thermal conductive particles with the phosphate glass, between the glass and fillers, the firing temperature was set to 500°C and h-BN particles were selected as high thermal conductive particles. Dense nitride phosphor particles dispersed h-BN/glass composites were successfully obtained by hot-pressing. Thermal conductivity normal to hot-pressing direction was higher than that parallel to hot-pressing direction, and it increased with an increase in the hot-pressing pressure and the quantity of dispersed h-BN particles because of higher density and better orientation of the h-BN particles. Consequently, the nitride phosphor particle dispersed h-BN/glass composites with the thermal conductivity of 9.4 W/(m−1·K−1) were obtained.
Ion exchangeable inorganic fibers based on sodium silicate have been successfully developed. The fibers have the ion exchange capacity of 83.8 meq·100 g−1 which is comparable to that of ion-exchangeable resin. Absorbing glass mat (AGM) for separators in lead-acid batteries was also successfully prepared with ion-exchangeable sodium silicate fibers. It was clarified by charge/discharge cycle test and morphological observation with scanning electron microscopy that the ion exchangeable AGM can inhibit the precipitation of PbSO4 particles on the surface of electrodes and consequently reduces the deterioration in coulomb efficiency during repetitive cycles. Furthermore it was also clarified that ion-exchangeable AGM can inhibit the precipitation of PbSO4 in separator itself notably. This will allow the reduction of thickness of separator and downsizing of lead battery body.