Multiple Phase Transition and Scaling Law for Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Copolymer in Aqueous Solution

作者：Liu Sijun; Li Lin^*

来源：ACS Applied Materials & Interfaces, 2015, 7(4): 2688-2697.

DOI：10.1021/am507749w

• micelle
• multiple phase transition
• scaling law
• gelation
• rheology

The multiple phase transition and the scaling behavior of a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (Pluronic F-127, PEO100-PPO65-PEO100) have been studied by micro-differential scanning calorimetry and rheology. The scaling behavior of the triblock copolymer was examined using the Winter-Chambon criterion to obtain the critical gel temperature Tgel and the scaling exponent n. n was found to decrease linearly with increasing copolymer concentration. A stable hard gel was formed, but the hard gel was transformed into a soft gel upon further heating. Increasing copolymer concentration led to the increase in the temperature of hard-soft gel transition, while the sol-gel transition temperature decreased with increasing copolymer concentration. A phase diagram has been determined, which is able to classify unimers, micelles, hard gel, and soft gel regions upon heating. In addition, the scaling relation of the plateau modulus Ge with copolymer concentration was also obtained as G(e) approximate to c(3.0) for both soft gel and hard gel.

• 出版日期2015-2-4