Liang Xiangfeng, Guo Chen, Ma Junhe, Wang Jing, Chen Shu, Liu Huizhou
Laboratory of Separation Science and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Graduate University of Chinese Academy of Sciences, Beijing 100080, China.
J Phys Chem B. 2007 Nov 22;111(46):13217-20. doi: 10.1021/jp074990n. Epub 2007 Oct 31.
Aggregation and disaggregation of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers, Pluronics P103 and P104, in aqueous solutions during a heating and cooling cycle were investigated by dynamic laser scattering (DLS) and 1H NMR spectroscopy. Temperature hysteresis was observed by DLS when cooling the copolymer aqueous solutions because larger aggregates existed at temperatures lower than critical micellization temperature (CMT), but no temperature differences were observed by NMR. This phenomenon was explained as the forming of water-swollen micelles at temperatures lower than CMT during the cooling process.
通过动态激光散射(DLS)和1H核磁共振光谱法,研究了聚环氧乙烷-聚环氧丙烷-聚环氧乙烷(PEO-PPO-PEO)嵌段共聚物(普朗尼克P103和P104)在加热和冷却循环过程中在水溶液中的聚集和解聚情况。当冷却共聚物水溶液时,通过DLS观察到温度滞后现象,因为在低于临界胶束化温度(CMT)的温度下存在较大的聚集体,但通过核磁共振未观察到温度差异。这种现象被解释为在冷却过程中,在低于CMT的温度下形成了水溶胀胶束。