The present work describes how the thermal response of some thermosensitive poly(N-isopropylacrylamide)-poly(ethylene glycol)-poly(N-isopropylacrylamide) (PNIPAM-PEG-PNIPAM) triblock copolymers of different compositions, in aqueous solution, estimated by the cloud point (CP) method, can be controlled by factors like polymer concentration (0.05–5 wt%) and composition (PNIPAM and PEG blocks length, overall polymer hydrophilicity), as well as by the nature and concentration (0.1–0.4 M) of some water-soluble additives. The experiments showed that CP decreased with polymer concentration and molecular weight (MW) of the PNIPAM block and increased with the MW of the PEG block. The influence of inorganic and organic salts through both their anion and cation, and short-alkyl chain organic nonelectrolytes through their alkyl chain architecture (linear or branched) and polarity of the functional group (alcohol, aldehyde, amine, carboxyl) was also investigated. Neither the composition nor the hydrophilicity of our triblock copolymers displayed any appreciable influence upon CP increase/decrease in the presence of additives. It was proved by hysteresis loop area measurements that NaCl addition increased the hysteresis effect of the polymer soluble - insoluble reversible transition.

本工作描述了如何通过水溶液分析法估算某些不同组成的热敏性聚（N-异丙基丙烯酰胺）-聚（乙二醇）-聚（N-异丙基丙烯酰胺）（PNIPAM-PEG-PNIPAM）三嵌段共聚物在水溶液中的热响应。浊点（CP）方法可通过诸如聚合物浓度（0.05-5 wt％）和组成（PNIPAM和PEG嵌段长度，整体聚合物亲水性）以及性质和浓度（0.1-0.4 M）等因素来控制一些水溶性添加剂。实验表明，CP随PNIPAM嵌段的聚合物浓度和分子量（MW）的降低而降低，并随PEG嵌段的MW的升高而提高。无机盐和有机盐通过其阴离子和阳离子的影响，通过烷基链结构（直链或支链）和官能团（醇，醛，胺，羧基）的极性研究了短烷基链有机非电解质。在添加剂的存在下，我们的三嵌段共聚物的组成和亲水性均未显示出对CP增/减的任何明显影响。通过磁滞回线面积测量证明，NaCl的添加增加了聚合物可溶-不溶可逆转变的磁滞效应。