부산대학교 도서관

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. Unlabelled Image • The effect of additives on PNIPAM-PEG-PNIPAM thermal response was studied • The thermal response can be controlled by block copolymer composition • The thermal response depends on the nature and concentration of additive • Triblock copolymer composition did not influence the magnitude of the additive effect • NaCl addition increased the hysteresis effect [ABSTRACT FROM AUTHOR]