杂臂星形聚两性电解质的合成及自组装行为

Synthesis and Self-Assembly Behaviors of Poly(Amino Acid) Based Miktoarm Star-Shaped Polyampholyte

联用"发散法"、"阴离子开环聚合"以及"点击化学法",成功合成了以聚(L-谷氨酸)(PLGA)及聚(L-赖氨酸)(PLL)为臂,以第1代树状聚酰胺-胺(D1)为核的AB2型杂臂星形聚两性电解质PLGA-b-D1-(PLL)2,表征了该非线型聚两性电解质的化学结构,并探讨了其在水溶液中的pH响应性自组装行为。研究结果表明,随溶液pH值的增加,PLGAb-D1-(PLL)2具有pH响应性多重胶束化行为。在pH值小于等电点时,形成以PLGA为核、带正电荷的PLL为壳的球型胶束;当pH高于等电点时则获得以带负电荷的PLGA为壳的短棒状胶束,并随pH的进一步增加转变为蠕虫状胶束,并在高pH值时二次自组装成分型结构。

A novel polypeptide-based miktoarm star-shaped polyampholyte, poly(L-glutamic acid)- b-D1-poly(Llysine)[PLGA- b-D1-(PLL)2],where D1 is the first generation of poly(amido amine),was synthesized by the combinationof divergent synthesis,' click reaction' and ring-opening polymerization. The molecular structure of this non-linear polyampholyte was characterized and the self-assembly behaviors in aqueous solutions were investigated.It is found that PLGA- b-D1-(PLL)2presents pH-responsive'schizophrenic' micellization behaviors with adjusting the pHvalues of the solutions. The spherical micelles with PLGA-core and positively charged PLL corona could be formed at pH below the isoelectric point(IEP), whereas the short rod-like micelles with negatively charged PLGA corona is found at pHs larger than IEP. These short rod-like micelles could be transformed into worm-like micelles and even hierarchically self-assemble into fractal structures with further increasing the pH to higher values.