Unusual Phase Transition Behavior of Poly(N-isopropylacrylamide)-co-Poly(tetrabutylphosphonium styrenesulfonate) in Water: Mild and Linear Changes in the Poly(N-isopropylacrylamide) Part

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• 作者：Ge Wang ; Peiyi Wu
• 刊名：Langmuir
• 出版年：2016
• 出版时间：April 19, 2016
• 年：2016
• 卷：32
• 期：15
• 页码：3728-3736
• 全文大小：549K
• 年卷期：0
• ISSN：1520-5827

文摘

In this paper, one LCST-type thermoresponsive poly(ionic liquid) (PIL), poly(tetrabutylphosphonium styrenesulfonate) (P[P_4,4,4,4][SS]), was introduced to poly(N-isopropylacrylamide) (PNIPAM) by two different ways, mixing and copolymerization. Interestingly, they show distinct thermoresponsive phase transition behaviors, evidenced by temperature-variable ¹H nuclear magnetic resonance and Fourier transform infrared in combination with the perturbation correlation moving window (PCMW) technique. The PNIPAM/P[P_4,4,4,4][SS] mixture exhibits a sharp and drastic phase transition, similar to that of pure PNIPAM. In the statistical copolymer, PNIPAM-co-P[P_4,4,4,4][SS], the thermosensitivity of P[P_4,4,4,4][SS] is largely suppressed, resulting in a linear, mild, and incomplete phase transition, which has never been reported before. This abnormal phenomenon is shown to arise from the outstanding hydration ability of P[P_4,4,4,4][SS]. Our findings should be conducive to improving our understanding of the interaction between LCST-type polymers with distinct structures and provide a new perspective for preparing thermoresponsive materials with linear phase transition behavior.