PEO-PPO-PEO嵌段共聚物在水溶液中的自组装行为及其应用

聚氧乙烯-聚氧丙烯-聚氧乙烯(PEO-PPO-PEO)嵌段共聚物是一类重要的非离子表面活性剂,在选择性溶剂中可以自组装成多种形貌的介观结构。对PEO-PPO-PEO嵌段共聚物在水溶液中自组装行为进行了综述,介绍了其自组装行为的实验研究技术;阐明了嵌段共聚物构型、分子量、温度、浓度、添加剂等因素对PEO-PPO-PEO嵌段共聚物聚集行为的调控和作用机理;介绍了嵌段共聚物自组装特性的热力学模型、分子模拟及计算机预报等研究方法和研究进展;重点介绍了PEO-PPO-PEO嵌段共聚物在介孔材料制备、药物载体、生物大分子分离、嵌段共聚物修饰等方面的应用。

Self-assembly of PEO-PPO-PEO block copolymer in aqueous solution and its application

Water-soluble poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers are high-molecular-weight nonionic surfactants, which exhibit the richest structural polymorphism in selective solvents. One of the most interesting features of the triblock copolymers is their self-association in aqueous solutions and their rich phase behavior. The microstructure resulting from the self-assembly of the triblock copolymer can vary from normal micelles in solution, through all types of normal and reverse lyotropic liquid crystals (normal micellar cubic, normal hexagonal, normal bicontinuous cubic, lamellar, reverse bicontinuous cubic, reverse hexagonal, reverse micellar cubic), to reverse micelles, as the relative volume fraction of the apolar components increases over that of the polar components. The self-assembly properties of PEO-PPO-PEO triblock copolymer in aqueous solutions are reviewed. Experimental techniques such as scattering techniques, spectroscopy techniques, viscometer, surface tension, ultrasonic velocimetry, differential scanning calorimetry, size exclusion chromatography and transmission electron microscopy for studying self-assembly behaviors of PEO-PPO-PEO triblock copolymers are introduced. Effects of structure of the block copolymer, molecular mass, temperature, concentration and additives such as inorganic salts, alcohols, oils, surfactants, ionic liquids and different block copolymers on self-assembly behaviors are introduced. A general overview of thermodynamic theories, molecular simulations and computer simulations of block copolymer micellar systems is also presented. Current applications of block copolymer as synthesis of mesoporous materials, controlled delivery of drug agents, separation of biomacromolecules and modification are also discussed.