Film formation from PS latex doped PNIPAM hydrogels at various heating and cooling rates

Film formation from polystrene (PS) latex doped poly(N-isopropylacrylamide) (PNIPAM) hydrogels was studied by using photon transmission technique. The transmitted light intensity, I tr was monitored during film formation process. Films were prepared by annealing, 10 wt% PS doped PNIPAM particles at five different heating and cooling rates at temperatures ranging from 10 to 100°C. I tr presented a hysteresis loops during heating–cooling cycles, which were explained by void closure and void reconstruction processes. The corresponding activation energies were measured during reversible film formation process. Void closure and void reconstruction models were introduced to produce the activation energies.