Synthesis of Microporous Silica Nanoparticles to Study Water Phase Transitions by Vibrational Spectroscopy

Microporous silica nanoparticles have been developed by a reverse microemulsion method utilizing zinc nanoclusters encapsulated hydroxyl-terminated polyamidoamine (PAMAM-OH) dendrimers as a soft template and made tunable within the outer diameter range of 20-50 nm with a core mesopore of 2-15 nm. Synthesized nanoparticles were used to study the effects of surface area and microporous volumes on the vibrational spectroscopy of water. These spectra reveal contributions from bulk interfacial/interparticle water, ice-like surface water, liquid-like water, and hydrated silica surfaces suggesting that microporous silica nanoparticles allow a way to probe silica water interactions at the molecular scale.