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 part of the silica−surfactant mesostructured materials without aggregation even at a high loading amount. The temperature dependence of the luminescence of pyrene revealed that the microviscosity of the probe microenvironments decreased gradually with decreasing temperature. The infrared absorption bands of the mesostructured materials confirmed the thermotropic change in the state of the surfactant aggregates.