Ge Lingling, Guo Rong, Zhang Xiaohong
School of Chemistry and Chemical Engineering, Yangzhou University, Jiangsu Province, People's Republic of China.
J Phys Chem B. 2008 Nov 20;112(46):14566-77. doi: 10.1021/jp802717p. Epub 2008 Jul 8.
Formation and structure transition of the complex composed of triblock copolymer F127 and nonionic surfactant TX-100 have been investigated by 1H NMR spectroscopy, dynamic light scattering (DLS), and isothermal titration calorimetry (ITC). Three TX-100 concentration regions are identified, within which TX-100/20 mg/mL F127 complex undergoes different temperature-induced structure transitions. In low concentration region (< 9.42 mM), F127 single molecular species (unimers) wrap around TX-100 micelles forming F127/TX-100 complex with TX-100 micelle as the skeleton at a lower temperature (5 degrees C), and the skeleton transfers to F127 micelle at higher temperature (40 degrees C); in intermediate TX-100 concentration region (9.42-94.85 mM), the skeleton of F127/TX-100 complex transfers from TX-100 micelle successively into F127 micelle and TX-100 micelle again upon heating. The interaction of F127 with TX-100 is saturated in high TX-100 concentration region (> 157.57 mM), and free TX-100 micelles coexist with larger clusters of F127/TX-100 complexes. In addition, TX-100-induced F127/TX-100 complex formation and structure transition are also investigated at constant temperatures. The results show that within 5-10 degrees C, F127 unimers mainly adsorb on the surface of TX-100 micelles just like normal water soluble polymers; in the temperature region of 15-25 degrees C, TX-100 micelles prompts F127 micelle formation. Within 30-40 degrees C, TX-100 inserts into F127 micelles leading to the breakdown of F127 aggregates at higher TX-100 concentrations, and the obtained unimers thread through TX-100 micelles forming complex with TX-100 micelle as skeleton.
通过核磁共振氢谱（1H NMR）、动态光散射（DLS）和等温滴定量热法（ITC）研究了三嵌段共聚物F127与非离子表面活性剂TX-100组成的复合物的形成及结构转变。确定了三个TX-100浓度区域，在这些区域内，TX-100/20 mg/mL F127复合物经历不同的温度诱导结构转变。在低浓度区域（<9.42 mM），F127单分子物种（单体）围绕TX-100胶束，在较低温度（5℃）下形成以TX-100胶束为骨架的F127/TX-100复合物，而在较高温度（40℃）下，骨架转变为F127胶束；在TX-100中间浓度区域（9.42-94.85 mM），加热时F127/TX-100复合物的骨架从TX-100胶束依次转变为F127胶束，然后再次转变为TX-100胶束。在高TX-100浓度区域（>157.57 mM），F127与TX-100的相互作用达到饱和，游离的TX-100胶束与更大的F127/TX-100复合物簇共存。此外，还在恒定温度下研究了TX-100诱导的F127/TX-100复合物形成及结构转变。结果表明，在5-10℃范围内，F127单体主要像普通水溶性聚合物一样吸附在TX-100胶束表面；在15-25℃温度区域，TX-100胶束促使F127胶束形成。在30-40℃范围内，TX-100插入F127胶束，导致在较高TX-100浓度下F127聚集体分解，所得单体穿过TX-100胶束，形成以TX-100胶束为骨架的复合物。
