Characterization of titanium alkoxide sol-gel systems designed for anti-icing coatings: I. Chemistry

Recent interest in sol-gel chemistry involving titanium alkoxide precursors has been prompted by the ability to control the morphology of the final TiO2 structure. The ligands used in these processes are typically sacrificial and are removed once the process is complete. In contrast, the sol-gel chemistry presented here is used to facilitate the slow release of the attached alkoxide ligands: tripropylene glycol (TPG) and glycerol. These compounds are first chemically reacted with titanium isopropoxide (TIP), then are slowly released through subsequent hydrolysis and condensation reactions. TPG and glycerol depress the freezing point of water and this sol-gel chemistry has been incorporated into a coating which has anti-icing properties. This article analyzes the precursor chemistry for various experimental conditions using TGA, FTIR, H-1 NMR, and model calculations.