Water-in-oil Pickering emulsion polymerization of N-isopropyl acrylamide using starch-based nanoparticles as emulsifier

Inverse Pickering emulsions stabilized by naturally derived particles are of interesting during the past decade. In this study, starch-based nanoparticles were used as a particulate emulsifier to stabilize a w/o Pickering emulsion. The effects of particle concentration and oil volume fraction on the emulsion type and stability were investigated in detail. Catastrophic phase inversion from o/w to w/o emulsions occurred at a volume fraction of oil of 0.3-0.4, without altering the particle wettability. Further, a linear relation existed between the average droplet diameter and total amounts of starch-based nanoparticles. The obtained starch-based nanoparticles also served as a Pickering stabilizer to conduct a w/o Pickering polymerization. Raspberry-like thermoresponsive starch-poly(N-isopropyl acrylamide) nanocomposites with a well-defined structure were synthesized.