Abstract
Aqueous solutions of thermo-responsive polymers represented by poly(N-isopropylacrylamide) (PNIPAM) exhibit a coil-to-globule phase transition followed by phase separation upon temperature increase. These polymers are promising smart materials that can form the basis for drug delivery systems. In order to apply these polymers as smart materials, it is necessary to acquire a precise knowledge on the dynamic behavior of phase separation. Recently, we developed a technique that combined a laser-induced temperature-jump with transient photometry to reveal the phase sepation dynamics in aqueous PNIPAM solutions. By using this particular technique, we demonstrated that the phase separation accerelated with increasing the polymer concentration. Furthermore, we found that the molecular weight of polymers and the stereoregularity of polymers influence the phase separation dynamics. Our observations will offer a new avenue for the design and development of thermo-responsive-polymer-based smart materials whose responsiveness can be controlled via the stereoregularity of the polymer.
