Discontinuous Crossover between Fast and Slow Kinetics at the Volume Phase Transition in Poly-N-isopropylacrylamide Gels
- 1 August 2000
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 39 (8B), L875
- https://doi.org/10.1143/jjap.39.l875
Abstract
The kinetics of the volume phase transition in N-isopropylacrylamide gels has been studied as a function of crosslinker concentration. The shrinking kinetics at the transition is extremely slow in gels with a standard composition which have been used widely in various experiments. A discontinuous crossover from slow to much faster kinetics were observed in both high- and low-crosslinker-concentration regions, where the characteristic time of the shrinking process changes abruptly by two to four orders of magnitude with a minute change of the crosslinker concentration. In spite of these marked changes in the kinetics, no anomaly was observed in the degree of equilibrium swelling in these regions. A mechanism leading to sudden changes in kinetics is discussed in terms of an inhomogeneous network structure which is dependent on crosslink density.Keywords
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