Dual Thermo- and pH-Responsive Materials Based on Starch

A simple and direct method for preparation of thermo- and pH- responsive materials based on starch is presented. Introduction of 2-hydroxy-3-butoxypropyl as hydrophobic group into starch developed thermo-responsive material, and further introduction of hydrophilic carboxymethyl group could produce dual thermo- and pH-responsive materials. The LCST of these starch-based materials can be easily adjusted at desired temperature between 4.5 and 57.0°C by controlling the molar substitution of 2-hydroxy-3-butoxypropyl and carboxymethyl groups. Furthermore, the LCST of 2-hydroxy-3-butoxypropyl-carboxymethyl starch was also highly sensitive to pH.