聚苯乙烯-b-聚谷氨酸苄酯刚柔嵌段共聚物的合成及其层状形貌考察  

SYNTHESIS AND INVESTIGATION OF PHASE-SEPARATED LAMELLAR MORPHOLOGIES OF ROD-COIL TYPE POLYSTYRENE-b-POLY(γ-BENZYL-L-GLUTAMATE) POLYPEPTIDE HYBRIDS

作　　者：吴进[1] 王琴[1] 汤双凤[1] 颜竹君[1] 

机构地区：[1]复旦大学材料科学系,上海200433

出　　处：《高分子学报》2013年第9期1151-1158,共8页Acta Polymerica Sinica

基　　金：博士学科点专项科研基金新教师基金(基金号200802461084);国家自然科学基金(基金号20904004);上海青年科技启明星计划(项目号10QA1400400)资助

摘　　要：以末端带胺基的聚苯乙烯(PS-NH2)为引发剂,利用N-羧酸内酸酐(N-carbonyl anhydride,NCA)法制备一种刚柔二嵌段共聚物聚苯乙烯-b-聚(γ-苄基-L-谷氨酸酯)(polystyrene-b-poly(γ-benzyl-L-glutamate),PS-b-PBLG)杂化聚肽,并研究该聚肽嵌段共聚物的分子结构、热性能、液晶性与自组装形貌的溶剂效应.以氢核磁共振波谱(1H-NMR)和凝胶渗透色谱仪(GPC)表征两嵌段的摩尔比、分子量及其分布.利用示差扫描量热分析仪(DSC)与光学显微镜(POM)考察材料的热性质与液晶性.由小角X射线散射(SAXS)分析得知,两嵌段组分呈交替分布层状结构,聚肽层中α螺旋链在不同溶剂中会发生不同程度折叠;通过透射扫描电镜(TEM)清楚观察到PS-b-PBLG在1,2-二氯乙烷(EDC)中α螺旋折叠形成了条纹式层状形貌,不同于1,1,2,2-四氯乙烷(TCE)中α螺旋完全伸展形成的锯齿式层状形貌.Using the primary amino-ended polystyrene（PS-NH 2） as the macroinitiator,diblock copolymers of polystyrene-b-poly（γ-benzyl L-glutamate）（PS-b-PBLG） polypeptide hybrids were synthesized by the ring opening polymerization of N-carbonyl anhydride（NCA） method.The molecular weight and its distribution（M w / M n = 1.4 ＂1.8） were characterized by GPC.Comparing with the first segment,the molar ratios of the compound could be confirmed by1H-NMR.The thermoproperties characterized by differential scanning calorimetry（DSC） indicate two temperature step changes at 10 ~ 20 ℃ and 70 ~ 80 ℃,corresponding to the two glass transitions of PBLG and PS,respectively.The texture of PS-b-PBLG in 1,1,2,2-tetrachloroethane（TCE） under a polarizing microscope（POM） shows relatively weak birefringence comparing with that of the PBLG homopolymer,but it still maintains some cholestericliquid crystalline properties.In structure of the shearoriented solid film,α-helical segments were arranged in hexagonal packing,while another larger period parallel to the helical axis was found in small-angle X-ray scattering（SAXS） pattern,indicating a phase-separated structure of alternative lamellar.The morphologies were observed through the transmission scanning electron microscope（TEM）.Unlike the zigzag-lamellar texture of films from TCE,the texture of films dried from 1,2dichloroethane（EDC） is stripe-shaped.The different morphology is due to the solvent effects on the rigidity of α-helix,which means the shorter cycle length should be attributed to the α-helical folding.It is therefore concluded the self-assembled structure of PS-b-PBLG is changed by the solvents.

关 键 词：杂化聚肽 刚-柔二嵌段共聚物 α螺旋链折叠 相分离 层状结构 

分 类 号：O631.3[理学—高分子化学]