The Effect of Preparation Temperature on Phase Transitions ofN-Isopropylacrylamide Gel

Abstract

The spinodal decomposition of N-isopropylacrylamide (NIPA) gels prepared at various onset temperatures, T on was studied by photon transmission. It was observed that the increase in turbidity is much faster in a gel prepared at higher T on than at lower T on values, which indicated that the NIPA-water system reaches the spinodal decomposition much faster for a gel prepared at high T on. It is understood that a NIPA gel prepared at high T on possesses more heterogeneities which are gained during gelation and has a low spinodal temperature, T s. However, NIPA gels prepared at lower T on values go to spinodal decomposition at higher T s values.