Structural Study on the UCST-Type Phase Separation of Poly(N-isopropylacrylamide) in Ionic Liquid

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• 作者：Hanako Asai ; Kenta Fujii ; Takeshi Ueki ; Shota Sawamura ; Yutaro Nakamura ; Yuzo Kitazawa ; Masayoshi Watanabe ; Young-Soo Han ; Tae-Hwan Kim ; Mitsuhiro Shibayama
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：February 12, 2013
• 年：2013
• 卷：46
• 期：3
• 页码：1101-1106
• 全文大小：376K
• 年卷期：v.46,no.3(February 12, 2013)
• ISSN：1520-5835

文摘

Upper critical solution temperature (UCST)-type phase separation behavior and its conformational change of well-defined poly(N-isopropylacrylamide) (pNIPAm) in deuterated room-temperature ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (d₈-[C₂mIm⁺][TFSA^{鈥?/sup>]), were investigated by means of dynamic light scattering (DLS) and small-angle neutron scattering (SANS) measurements. From the temperature dependence of time-averaged scattering intensity obtained by DLS, it was found that the cloud points of pNIPAm/d₈-[C₂mIm+][TFSA鈥?/sup>] solutions increased with molecular weight (M_w) and concentration. In addition, it was found that there are two relaxation modes of pNIPAm in the IL solutions. From SANS measurements, the radius of gyration, R_g, and the Flory鈥揌uggins interaction parameter, 蠂, were evaluated as a function of temperature during the phase separation.}