表面活性剂双水相分配效应的研究

When cationic and anionic surfactants are mixed at certain concentration, the solution separates spontaneously into two aqueous phases with a clear interfacial boundary between them. Such phase systems are called aqueous surfactant two-phase systems (ASTP). Since the concentration and organized molecular assemblies of surfactants in two phases are very different, and the ASTP are very dilute, ASTP can be used as a new partitioning system for the separation of chemicals and biomaterials. This project studied the partition function of ASTP. (1) The formation of ASTP was studied, including the effect of molecular structure and concentration of surfactants, inorganic salts and organic additives, buffers, pH and temperature on formation of ASTP. Two kinds of ASTP were obtained; (2) The phase behaviors and physico-chemical properties of ASTP were studied. The structure of organized molecular assemblies in ASTP was measured by TEM and DLS methods. A very special highly structure organized molecular assemblies, the tube-like vesicle, was observed in ASTP; (3) The interfacial properties of ASTP were studied. The interfacial tensions between the two phases were measured by spinning drop methods. Two kinds of curves of interfacial tension/molar ratio were obtained; (4) A new aqueous two-phase system was obtained by mixing cationic-anionic surfactants and polymers, which has advantages when compared with ASTP, and can also be used for the partitioning of proteins; (5) It was found that an new aqueous three-phase system (A3PS) could be formed spontaneously when one Triton X nonionic surfactant and two polymers (e.g. PEG and Dextran) were mixed together. The formation, phase behavior and protein portioning in A3PS were studied, and the interfacial tensions between these three phases were measured by the spinning drop method; (6) The phase behavior of cationic-anionic surfactant mixtures was further studied, as the basis of ASTP investigation. The homogeneous solutions of mixed cationic-anionic surfactants were obtained at very high concentration of mixed surfactants and total molar ratios. It was observed that alkysulfate and alkylsulfonate behave quite differently when they were mixed with cationic surfactants, even with some results unexpected. The results showed that just contrary to the single surfactants, the solubility of alkylsulfonate- alkyl quaternary ammonium is much higher than that of alkylsulfate- alkyl quaternary ammonium. Besides, the two kinds of catanionic surfactant mixed systems were quite distinct in their phase behaviors, aggregate properties and ASTP.

表面活性剂双水相是指正负离子表面活性剂混合稀水溶液自发分成的两个水相。可作为新型分配体系，用于化学与生物物质的分离及分析。本项目研究各类碳氢和碳氟表面活性剂双水相中化学与生物物质的分配行为；研究表面活性剂、双水相、被分配物质及外加物质等的性质与分配的关系；总结分配规律；探讨分配机理。为发展新型分离体系提供理论基础。