THERMOTROPIC BEHAVIOR OF THE SILICA-ALKYLTRIMETHYLAMMONIUM CHLORIDE MESOSTRUCTURED MATERIALS

The characteristics of the thin films of silica-alkyltrimethylammonium chloride mesostructured materials have been investigated by means of the fluorescence of pyrene as:well as the infrared spectra at variable temperatures. Pyrene molecules were incorporated in the hydrophobic p art of the silica-surfactant mesostructured materials without aggregat ion even at a high loading amount. The temperature dependence of the l uminescence of pyrene revealed that the microviscosity of the probe mi croenvironments decreased gradually with decreasing temperature. The i nfrared absorption bands of the mesostructured materials confirmed the thermotropic change in the state of the surfactant aggregates.