Fukumoto Hirokazu, Ishihara Kazuhiko, Yusa Shin-Ichi
Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, Hyogo 671-2280, Japan.
Department of Materials Engineering, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
Polymers (Basel). 2021 Jan 1;13(1):148. doi: 10.3390/polym13010148.
A mixed aqueous solution of hydrophilic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and poly(acrylic acid) (PAAc) becomes cloudy under acidic conditions at room temperature. The pendant carboxylic acid groups in PAAc form hydrogen bonds with the ester and phosphate groups in PMPC. While the polymers aggregate under acidic conditions, neither one associate under basic conditions because of the deprotonation of the pendant carboxy groups in PAAc. We observed that the interpolymer complex formed from PMPC, and PAAc was dissociated in aqueous solutions with increasing temperature, which is an upper critical solution temperature behavior. With increasing temperature, the molecular motion increased to dissociate the interpolymer complex. The phase transition temperature increased with increasing polymer and salt concentrations, and with decreasing pH.
亲水性聚（2-甲基丙烯酰氧基乙基磷酰胆碱）（PMPC）和聚丙烯酸（PAAc）的混合水溶液在室温酸性条件下会变浑浊。PAAc中的侧链羧酸基团与PMPC中的酯基和磷酸基团形成氢键。虽然聚合物在酸性条件下会聚集，但在碱性条件下两者都不会缔合，因为PAAc中侧链羧基会发生去质子化。我们观察到，由PMPC和PAAc形成的聚合物间复合物在水溶液中会随着温度升高而解离，这是一种上临界溶液温度行为。随着温度升高，分子运动增强，聚合物间复合物解离。相转变温度随着聚合物浓度、盐浓度的增加以及pH值的降低而升高。
