Kinetics of solvent responsiveness in poly(N,N‐dimethylacrylamide) hydrogels of different morphology
Crosslinked poly(N,N‐dimethylacrylamide) hydrogel samples were synthesized with various total comonomer concentrations and crosslinker ratios in the reacting mixture, and at two different temperatures: room temperature and the boiling point of the reacting mixture, about 80 °C. During gelation of samples prepared at the higher temperature, the bubbles of the boiling system were trapped in positions homogeneously distributed, and post‐gel reactions fixed them. These samples were macroporous, showing about three times the swelling capacity of conventional hydrogels synthesized at room temperature with the same composition. Both types of hydrogel swollen at equilibrium in water deswelled exponentially with time when they were immersed in acetone or dioxane. The rate of shrinking was higher for macroporous than for conventional samples and it was smaller in dioxane, the solvent with higher viscosity (η), although there was no proportionality to the solvent fluidity, η−1. The morphology, which was in the scale of micrometres (as revealed by scanning electron microscopy), played a minor role in the shrinking rates of both types of gels. The excess swelling and the faster solvent response of macroporous gels were ascribed to the store and draining capacity of macropores at the millimetre scale. Copyright © 2005 Society of Chemical Industry
No Supplementary Data
No Article Media
Document Type: Research Article
Affiliations: Departamento de Ciencias y Técnicas Fisicoquímicas, Facultad de Ciencias, Universidad a Distancia (UNED), 28040 Madrid, Spain
Publication date: August 1, 2005
More about this publication?