Hydrolysis of silica sources: APS and DTSACl in microencapsulation processes

The process of formation of silica shells around emulsion droplets was investigated. The 1H-NMR spectroscopy was applied to follow the silica shell formation around emulsion droplets by hydrolysis and condensation of selected silanes in the emulsion system. (3- aminopropyl) triethoxysilane (APS) and dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DTSACl) were used as silica sources in microencapsulation process. The NMR analysis revealed strong dependence of the hydrolysis reaction rate on pH. Obtained information allowed selecting the optimal conditions for the formation of the capsules with silica shells. The obtained capsules' suspensions were stable for several weeks.