Encapsulation of Methyl Red pH‐Indicator into a Sol‐Gel Matrix

Abstract

Encapsulation of methyl red pH indicator into transparent monolithic silica matrices was made via the acid‐catalyzed sol‐gel reaction of tetraethylorthosilicate and methyl red indicator. The immobilized methyl red shows behavior similar to its solution counterpart. It retains its structure during the sol‐gel reactions in terms of response to pH. Polarized light microscopy and the surface morphology indicated that methyl red molecules are strongly interacted within the host silica network.