Watanabe Tomohisa, Wang Yubo, Ono Tomoko, Chimura Satoru, Isono Takuya, Tajima Kenji, Satoh Toshifumi, Sato Shin-Ichiro, Ida Daichi, Yamamoto Takuya
Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan.
Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Hokkaido, Japan.
Polymers (Basel). 2022 Apr 29;14(9):1823. doi: 10.3390/polym14091823.
The topology effects of cyclization on thermal phase transition behaviors were investigated for a series of amphiphilic Pluronic copolymers of both hydrophilic-hydrophobic-hydrophilic and hydrophobic-hydrophilic-hydrophobic block sequences. The dye solubilization measurements revealed the lowered critical micelle temperatures () along with the decreased micellization enthalpy (Δ) and entropy (Δ) for the cyclized species. Furthermore, the transmittance and dynamic light scattering (DLS) measurements indicated a block sequence-dependent effect on the clouding phenomena, where a profound decrease in cloud point () was only found for the copolymers with a hydrophilic-hydrophobic-hydrophilic block sequence. Thus, the effect of cyclization on these critical temperatures was manifested differently depending on its block sequence. Finally, a comparison of the linear hydroxy-terminated, methoxy-terminated, and cyclized species indicated the effect of cyclization to be unique from a simple elimination of the terminal hydrophilic moieties.
针对一系列具有亲水-疏水-亲水和疏水-亲水-疏水嵌段序列的两亲性普朗尼克共聚物，研究了环化对热相变行为的拓扑效应。染料增溶测量结果表明，环化物种的临界胶束温度降低，同时胶束化焓（Δ）和熵（Δ）也降低。此外，透过率和动态光散射（DLS）测量表明，对浊度现象存在嵌段序列依赖性效应，其中仅在具有亲水-疏水-亲水嵌段序列的共聚物中发现浊点（）显著降低。因此，环化对这些临界温度的影响因其嵌段序列而异。最后，对线性羟基封端、甲氧基封端和环化物种的比较表明，环化的影响不同于简单地消除末端亲水部分。
