Preparation, Structure Characterization And Thermal-Ejecting Effect Of SPLC Hybrid Liquid Crystal And Its Derivative Mesoporous Materials

In the middle eighties of the twentieth century, nano-materials had become the most advanced researching field of materials science and solid-state physics. And when it reached the middle of nineties, the self-assembled system with nano-building-block became the focus of the research on nano-materials. Mesoporous material is an important kind of such self-assembled materials. Mesoporous materials possess many excellent characteristics such as environmental benign preparing method of soft solution, adjustable pore diameter between 2 nm to 30 nm and high surface area and porosity (for silica based MCM-41: 1050m~2/g and 0.93cm~3/g, respectively). Benefiting from these advantages, mesoporous materials were considered having great potentials in the fields of chemistry, physics, materials science, biology, medicine and information. Nowadays, mesoporous materials have been found to be successful in catalysis and absorption applications. In other application fields, large area functional mesoporous materials possess great potential. C.J. Brinker group from University of New Mexico has successfully prepared large area membrane materials possessing various micro-symmetric structures and macro-morphologies by dip coating process (membrane thickness of 0.5 micrometer each time) through controlling the solvent evaporation. Mesoporous membrane and bulk mesoporous product PTO-1 with roughly 1.2 millimeter thickness was successfully prepared by using SPLC (Silica-PE6400 Liquid Crystal) method. A novel nano-effect from these mesoporous products, named "Thermal-Ejecting Effect"was firstly discovered and studied. The formation mechanism for Thermal-Ejecting Effect is identified as the fast physical ejection of PE6400 micelles from inside pore channels by the driven of high temperature and pressure steam under certain temperature. This effect is not induced by PE6400 decomposing in oxygen atmosphere. The temperature of Thermal-Ejection Effect is dominated by pore size and its distribution and the interactions between PE6400 micelles and pore wall, which may be lower (for membrane: 40.3℃lower; for PTO-1: 23.3℃lower) or higher (for KH580 modified PTO-1: 62.6℃higher) than that of PE6400 decomposing (256.1℃). On the other hand, the temperature ranges for mesoporous membrane, PTO-1 and KH580 modified PTO-1 are 106.5℃, 98.8℃and 96.6℃narrower than that of PE6400 decomposing.