聚異丙基丙烯醯胺半稀釋溶液物理性質

Physical Properties of Poly(N-isopropylacrylamide) Semi-dilute Solution

呂文智(Wen-Chih Lu)

指導教授 ： 余子隆

元智大學/工程學院/化學工程與材料科學學系/碩士(2003年)

摘要

聚異丙基丙烯醯胺poly(N-isopropyl acrylamide) (poly(NIPAM))的化學結構中具有疏水性的主鏈及親水性的支鏈。由於其特殊的化學結構造成它在水溶液中的分子形態對溫度變化有極大的敏感性，會隨著溫度的上升下降有可逆的物理形態變化。
本論文研究5wt% poly(NIPAM)在三種不同溶劑的半稀釋溶液(semi-dilution solution)的黏彈性質及粒徑分布隨溫度之變化。實驗數據顯示，5wt% poly(NIPAM)/H2O溶液及5wt% poly(NIPAM)/D2O溶液，是屬於LCST溶液，在溶液中poly(NIPAM)分子有聚集現象。它們的θ-Temp分別是31.7℃及32℃，而LCST溫度分別是33.2℃及33.8℃。在溫度介於θ-Temp及LCST 之間，聚集粒子粒徑及黏度會隨溫度上升而急速下降。在LCST以上，則產生相分離(phase separation)。Poly(NIPAM)/ D2O溶液的黏度及聚集粒子粒徑大於poly(NIPAM)/H2O溶液。Poly(NIPAM)/THF溶液則表現出一般polymer good solvent solution現象，是屬於LCST溶液，DLS量測不到聚集粒子，它的黏度隨溫度上升而下降。三種不同溶液的物理現象應是溶劑與poly(NIPAM)的氫鍵強度及溶劑對poly(NIPAM)的溶解參數的交互影響產生。

關鍵字

相分離 ； 氫鍵 ； 溶解參數

並列摘要

Poly (NIPAM) has a chemical to hydrophobic main chain and hydrophilic side chains. Molecular chain conformation of poly (NIPAM) is sensitive to temperature due to its special chemical structure that has reversible physical conformation with temperature. In this thesis, solution properties of 5 wt% poly (NIPAM) solutions which three different solvents were investigated using rheometer and dynamic light scattering (DLS). The rheometer experimental results and DLS particle size data showed that there are shear induced polymer aggregations in these three solutions. The zero shear viscosity and shear induced aggregation viscosity data revealed that poly (NIPAM)/H2O and poly (NIPAM)/D2O are LCST solution and poly (NIPAM)/THF is an UCST solution. The hydrogen bonds between H2O (or D2O) with poly (NIPAM) molecules and the hydrophobic of poly (NIPAM) lead poly (NIPAM)/H2O and poly (NIPAM)/D2O solutions to be LCST. Poly (NIPAM)/THF behaves like an ordinary polymer solution owing to THF has a similar solubility parameter as poly (NIPAM) has.

並列關鍵字

Poly (NIPAM) ； H-bond ； Solubility parameter

參考文獻

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