两亲聚肽/螺烯的电荷复合自组装行为研究

Study of Charge-Conjugated Self-Assembly Behavior of Amphiphilic Block Copolypeptides/Helicene

研究了包含聚肽嵌段的两亲共聚物聚乙二醇-b-聚(L-谷氨酸)(PEG-b-PGlu)与4-甲基-4-氮杂[4]螺烯鎓离子(Me[4]H)的电荷复合自组装行为,讨论了聚肽链段长度、谷氨酸单元与螺烯物质的量比、pH值等因素对组装体形貌的影响.研究发现,当刚-柔型嵌段聚合物与刚性、大尺寸并具有诱导作用的小分子共同组装时,遵循与柔性大分子电荷复合组装完全不同的规律.PEG-b-PGlu/Me[4]H的电荷复合组装体形貌由π-π堆叠作用、两亲嵌段聚肽的亲疏水比、PGlu链段的刚硬程度共同决定,这些作用在组装过程中相互制约,当π-π堆叠作用占主导地位时,得到以指针状和条带状等平面结构为主的组装形貌.

Amphiphilic block copolypeptides of polyethylene glycol-b-poly(L-glutamic acid)(PEG-b-PGlu)were synthesized to self-assemble with 4-methyl-4-aza[4]helicene onium ion(Me[4]H)in water through charge-conjugation.The morphology of the assemblies was studied by varying PGlu block length,the molar ratio of Glu unit/Me[4]H and pH value.It was found that when rigid-flexible block copolymers were assembled together with small molecules which had rigid,large size and inductive effect,they would follow a completely different law from the charge-conjugated assembly of flexible macromolecules.The self-assemblies were controlled by theπ-πstacking of helicene,together with the volume fraction of the hydrophobic parts and the rigidity of PGlu segments.These effects restricted each other in the assembly process.Whenπ-πstacking was dominant,assembly morphologies with pointer-like and strip-like planar structures were obtained.