PNIPAM线性链与凝胶在二元溶剂中相变的变温NMR研究  

NMR Studies on Phase Separation of Linear PNIPAM and Gel in Binary Solvents

作　　者：王念[1,2] 茹阁英[1] 王立英[1] 冯继文[1] 

机构地区：[1]波谱与原子分子物理国家重点实验室,武汉磁共振中心(中国科学院武汉物理与数学研究所),湖北武汉430071 [2]中国科学院研究生院,北京100049

出　　处：《波谱学杂志》2010年第3期461-469,共9页Chinese Journal of Magnetic Resonance

摘　　要：通过对聚N-异丙基丙烯酰胺(PNIPAM)水溶液和凝胶在水和甲醇混合溶剂中的1HNMR谱图以及弛豫时间(T1与T2)等多种NMR参数随温度变化的研究,发现PNIPAM大分子的基团质子NMR信号、溶剂的弛豫时间都可以用来灵敏表征PNIPAM在二元溶剂中的相变行为.在PNIPAM凝胶中,温度升到LSCT以上,溶剂峰由单峰变为双峰,分别对应于受限在大分子网络内的受限溶剂和排除到大分子网络外的自由溶剂,两者的弛豫时间存在明显差异.在PNIPAM溶液中,溶剂峰在相变前后并没有显著变化.通过PNIPAM溶胀在wa-ter/alcohol混合溶剂中的相变研究进一步证实了PNIPAM与不同溶剂之间的相互作用强弱.In this article,the phase separation of linear PNIPAM and gel in water/methanol binary solvents was studied by the measurements of NMR spectra and relaxation times.It was found that 1H NMR spectrum of PNIPAM,relaxation times of solvents changed dramatically when phase transition occurred.When PNIPAM gel in binary solvents was heated above the LCST only part of the solvents was expelled from the polymer networks and the other part remained inside the polymer networks,resulting in two distinct type of solution.Comparison the compositions of two distinct solution provides a convenient,direct means of characterizing the preferential adsorption of solvent on polymer.On the contrary,there was no obviously change of the solution peaks from 1H NMR spectrum as linear PNIPAM dissolved in water/methanol binary solvents.

关 键 词：核磁共振(NMR) 聚N-异丙基丙烯酰胺 相变 凝胶 

分 类 号：O482.53[理学—固体物理]