Temperature dependent phase behavior of PNIPAM microgels in mixed water/methanol solvents
Temperature dependent phase behavior of PNIPAM microgels in mixed water/methanol solvents
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DOI：
10.1002/polb.23194
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发表时间：
2013-07-15
影响因子：
--
通讯作者：
Richtering, Walter
中科院分区：
文献类型：
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作者：
Kojima, Hiroyuki;Tanaka, Fumihiko;Richtering, Walter
用动态光散射（DLS）和小角中子散射（SANS）研究了聚N-异丙基丙烯酰胺（PNIPAM）微凝胶在不同组成的水/甲醇混合体系中的温度依赖性相行为。使用DLS，可以准确、直接地测量扩散系数，从而测量颗粒的尺寸;通过这种方法也可以很容易地检测到不同溶剂中相变温度的变化。在D2 O/MeOD混合物中进行SANS测量，证实了DLS的一些结果。此外，SANS测量提供了在不同溶剂中的颗粒结构的有价值的信息。将实验结果与Tanaka等人提出的竞争水合理论进行了比较，发现理论与实验结果吻合较好，并得到了理论预测：在相变温度附近，凝胶中甲醇沿着链的组成高于外溶液的组成，而凝胶内部的甲醇组成低于外溶液的组成. (c)2012 Wiley Periodicals，Inc.聚合物科学杂志B部分：聚合物。2013，51，1100-1111
Temperature dependent phase behavior of poly(N-isopropylacylamide) (PNIPAM) microgels in water/methanol mixtures of different composition was studied with dynamic light scattering (DLS) and small-angle neutron scattering (SANS). Using DLS, it is possible to measure the diffusion coefficient, and thus the size of particles exactly and directly; the variation of the phase transition temperature in the different solvents is also easy to detect by this method. With SANS measurements in D2O/MeOD mixtures, some of the DLS results were confirmed. Moreover, SANS measurements give valuable information on the particle structure in different solvents. The experiments were compared with the theory of competitive hydration introduced by Tanaka et al. We found a good agreement of theory and experiment, and obtained the theoretical predictions: around the transition temperature, the composition of the bound methanol along the chains is higher than that of the outer solution, while the whole methanol composition inside the gel is lower. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym. Phys. 2013, 51, 1100-1111