Abstract
We prepared thermo-responsive polymer hydrogels by γ0-ray irradiation of aqueous solutions of N, N-diethylacrylamide at different temperatures below and above its lower critical solution temperature (LCST). Poly(N, N-diethylacrylamide) gel had a transparent and homogeneous structure when the radiation-induced polymerization and crosslinking were carried out below the LCST (25 °C) of the polymer. On the other hand, cloudy and heterogeneous gels were formed at temperatures above the LCST of the polymer (>35 °C). From environmental scanning electron microscopy observations, the gels prepared at 35 and 40 °C were seen to show sponge-like bi-continuous porous structures, while those prepared at 50 °C showed a porous structure consisting of interconnected microspheres. For temperature changes between 10 and 40 °C, gels with porous structures showed rapid volume transitions on a time scale of about a minute, not only for shrinking but also for swelling processes, which is in remarkable contrast to the porous poly(N-isopropylacrylamide) hydrogels.
Original language | English |
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Pages (from-to) | 505-512 |
Number of pages | 8 |
Journal | Colloid and Polymer Science |
Volume | 287 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2009 Jan 28 |
Keywords
- Bi-continuous structure
- Gel
- Microsphere
- Poly(N, N-diethylacrylamide)
- Volume transition
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Polymers and Plastics
- Colloid and Surface Chemistry
- Materials Chemistry