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以胆固醇和谷氨酸苄酯为主要出发原料,采用可逆加成-断裂链转移(RAFT)自由基聚合、氨基酸环内酸酐(NCA)开环聚合(ROP)以及“点击化学”(click chemistry)组合方法,设计、合成了系列具有刚性液晶元侧基的聚甲基丙烯酸羟乙酯胆固醇碳酸酯-嵌段-聚谷氨酸苄酯(PHEMAChol-b-PBLG),并通过核磁共振(NMR)、红外光谱(FTIR)、凝胶渗透色谱(GPC)和静态光散射(SLS)对其化学结构进行了表征.运用热重分析仪(TGA)、热台偏光显微镜(POM)和示差扫描量热仪(DSC)研究了系列共聚物的热稳定性、液晶相结构及相转变行为,并通过固体红外、13C固体核磁共振(13C CP/MAS)和X射线衍射仪(XRD)研究了PBLG均聚物及系列嵌段共聚物中聚氨基酸多肽链段的二级结构.研究结果表明,系列嵌段共聚物均具有良好的热稳定性,表现为近似向列相的液晶织构,PBLG链段趋于呈刚直棒状的α-螺旋构型,且其多肽链段越长,二级结构越规整.进一步采用圆二色谱(CD)和透射电镜(TEM)对系列嵌段共聚物在四氢呋喃溶液中的二级结构及自组装行为进行了研究,制备得到纺锤形自组装聚集体和大复合胶束,并通过变性酸三氟乙酸的引入实现对嵌段共聚物中PBLG的二级结构及相应自组装聚集体形貌的有效调控.
Cholesterol and benzyl glutamate were used as the starting materials, and the free radical polymerization by reversible addition-fragmentation chain transfer (RAFT), ring opening polymerization by amino acids (ROP) and click (PHEMAChol-b-PBLG), a series of poly (hydroxyethyl methacrylate) cholesteryl carbonate with a rigid liquid crystal unit side group was designed and synthesized. NMR, FTIR, GPC and SLS were used to characterize the chemical structures of these compounds.Using thermal gravimetric analyzer (TGA), thermal Polarizing microscope (POM) and differential scanning The thermal stability, the liquid crystal phase structure and the phase transition behavior of the copolymers were investigated by DSC. The effects of PBLG on the surface of PBLG were investigated by solid-state infrared, 13C CP / MAS and X-ray diffractometry (XRD) Homopolymer and series of block copolymers of polyamino acid polypeptide segments secondary structure.The results show that the series of block copolymers have good thermal stability, the performance of the nematic liquid crystal structure of the approximate line, PBLG chain The segment tends to be rigid rod-like α-helical configuration, and the longer the polypeptide segment, two The more regular the structure.The secondary structure and self-assembly behavior of the block copolymers in tetrahydrofuran solution were further studied by circular dichroism (CD) and transmission electron microscopy (TEM), and the spindle-shaped self-assembled aggregates and large Composite micelles. Through the introduction of denatured acid trifluoroacetic acid, the secondary structure of PBLG in the block copolymers and the morphology of the corresponding self-assembled aggregates were effectively controlled.