Summary
The role of the preparation temperature of poly(N-isopropylacrylamide) (PNIPA) gels on their swelling behavior in water and in aqueous solutions of sodium dodecylbenzenesulfonate was investigated. PNIPA gels were prepared by free-radical crosslinking copolymerization of N-isopropylacrylamide and N,N'-methylene(bis) acrylamide in water at fixed monomer and crosslinker concentrations. The equilibrium swelling ratio of the gels increases first slightly up to about 20°C then rapidly with increasing gel preparation temperature. Magnitude of the collapse transition in water at 34°C becomes larger as the gel preparation temperature increases. Calculations indicate a decrease in the effective crosslink density of PNIPA gels with increasing preparation temperature. The gels prepared at temperatures higher then 20°C were heterogeneous consisting of highly crosslinked regions interconnected by the PNIPA chains.
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Received: 3 May 2000/Revised version: 3 July 2000/Accepted: 17 July 2000
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Sayil, Ç., Okay, O. The effect of preparation temperature on the swelling behavior of poly (N-isopropylacrylamide) gels. Polymer Bulletin 45, 175–182 (2000). https://doi.org/10.1007/s002890070046
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DOI: https://doi.org/10.1007/s002890070046