Synthesis and properties of water-soluble silica nanoparticles

Surface Activity of Smart Hybrid Polysiloxane-co-N-isopropylacrylamide Microgels

Amphiphilic smart gels of different sizes (macro, micro, and nano) are widely used in advanced medical, industrial, and environmental applications. They are sensitive, responsive to different environments, and possess a high surface activity to adsorb onto different interfaces. In this study, new amphiphilic alkoxysilane-containing microgels, hybrid polysiloxane microgel, and silica nanoparticles were prepared using a cross-linking surfactant-free cross-linking polymerization technique for N-isopropylacrylamide (NIPAm) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) monomers. Vinyltrimethoxysilane (VTS) was used as a silane precursor in the cross-linking polymerization to hydrolyze with tetraethoxysilane (TEOS) in ammonia using an emulsion technique, to create polysiloxane microgel and silica nanoparticles. The surface activity measurements confirmed that NIPAm/VTS had a higher surface activity than NIPAm/AMPS-VTS microgels and their hybrid polysiloxane microgel owing to the differences of the cross-linking of microgels from the center to the microgel periphery, which alter their morphologies.