Temperature‐Triggered Modification of Polymer‐ Solvent Interactions: From Fluid‐to‐Gel Transitions to Particle Capture

Abstract

AbstractTemperature‐responsive polymers are of considerable interest in the literature. In this work the ability to combine temperature‐responsive polymer‐solvent interactions with architectural control to achieve a range of macroscopic effects is considered. The first part of the work considers poly(DEA) (N,N‐dieth ylacrylamide) microgel particles. The particles exhibit temperature‐triggered particle collapse at temperatures more than ca. 27 °C. As a consequence concentrated temperature‐responsive microgel dispersions change from gels to fluids when heated. The opposite effect is observed when dispersions or emulsions are stabilised by temperature‐responsive polymer surfactants. Recent results involving a gel‐forming castor oil‐in‐water emulsion are considered. The gelled emulsion releases a model drug (lidocaine) according to first‐order kinetics. We extend the principle of temperature‐triggered control of particle‐surface interactions to test a new approach for immobilising particles on surfaces. The method consists of electrodepositing Laponite particles onto a carbon surface, grafting of poly(NIPAM) (N‐isopropylacrylamide) onto the deposited particles and then increasing the temperature of the modified surface to trigger capture of dispersed polystyrene particles. This new approach uses chemistry that is potentially applicable to any conductive surface.