Collapse of thermosensitive polyelectrolyte semi-interpenetrating networks

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• 作者：Elena Yu. Kozhunova ; ^{kozhunova@polly.phys.msu.ru} ; Elena E. Makhaeva ; Alexey R. Khokhlov
• 关键词：Thermosensitive ; Hydrogel ; Polyelectrolyte
• 刊名：Polymer
• 出版年：2012
• 出版时间：25 May, 2012
• 年：2012
• 卷：53
• 期：12
• 页码：2379-2384
• 全文大小：441 K

文摘

Thermosensitive ionic semi-interpenetrating polymer networks (semi-IPNs) based on poly(N-isopropylacrylamide) (PNIPAAm) and poly(styrene sulfonic acid sodium salt) (PSS) were synthesized, and their properties, such as conversion, swelling ratio and swelling/shrinking kinetics, were studied at different PSS fractions and molecular weight (MW). It is shown that studied semi-IPN hydrogels undergo shrinking under temperature increase. Swelling behavior and volume transition temperature of the semi-IPNs is controlled by the polyelectrolyte fraction. The increase of PSS MW allows obtaining of stable semi-IPN hydrogels. A novel phenomenon of collapse irreversibility in PNIPAAm-PSS semi-IPNs is reported. In contrast to PNIPAAm hydrogels, semi-IPNs of PNIPAAm with immobilized polyelectrolyte do not restore their volume when they reswell after shrinking. The magnitude of this effect is connected to the charged polyelectrolyte fraction.