MICELLAR FORMATION OF SODIUM DODECYL-SULFATE IN SOL-GEL GLASSES PROBED BY PYRENE FLUORESCENCE

The fluorescence of pyrene probe molecules was measured in the sol-gel reaction system of tetraethyl orthosilicate and various concentrations of sodium dodecyl sulfate (SDS). The ratio of the intensity of the third peak to the first peak (I3/I1) was markedly different in the sol, gel, and xerogel stages. At low SDS concentrations, I3/I1 decreased during desiccation, indicating an increase in the environmental polarity of pyrene. In contrast, at high SDS concentrations, I3/I1 increased during desiccation, indicating a decrease in environmental polarity. In the latter case, I3/I1 had values similar to those for micellar solutions of SDS, which means that the environment of pyrene resembled that of micelle-solubilized pyrene. The results suggest that the micelles of SDS are trapped in the sol-gel glasses.