Novel Self-assembling Amino Acid-derived Block Copolymer with Changeable Polymer Backbone Structure
Novel Self-assembling Amino Acid-derived Block Copolymer with Changeable Polymer Backbone Structure
复制标题
具有可变聚合物主链结构的新型自组装氨基酸衍生嵌段共聚物
DOI：
10.1021/acs.langmuir.6b01617
复制
发表时间：
2016
期刊：
影响因子：
3.9
通讯作者：
N. Higashi,
中科院分区：
文献类型：
--
作者：
T. Koga;E. Aso;N. Higashi,
近年来，嵌段共聚物作为开发新型纳米结构材料的潜在构件引起了人们的极大关注。本文报道了一种新型的具有可变主链结构的自组装嵌段共聚物--聚(Fmoc-Ser)酯-b-PST，它是由9-荧甲氧基甲氧基丝氨酸缩聚(Fmoc-Ser)与可逆的苯乙烯(St)加成-断裂链转移(RAFT)聚合反应合成的。这种嵌段共聚物通过碱诱导有机溶剂中Fmoc基团的去保护而引发的多O，N-酰基迁移，直接将主链结构从聚酯转化为多肽。这种聚合物到聚合物的转化被发现在不降低聚合度的情况下定量地发生，并导致嵌段共聚物的自组装性质的急剧变化。通过傅立叶变换红外光谱、原子力、透射电子显微镜和扫描电子显微镜等手段对产物进行了形态分析，发现所合成的嵌段共聚物在甲苯中自组装成直径约为300 nm的囊泡状中空纳米球。在这种情况下，由聚酯生成的多肽嵌段形成β-Sheet结构，表明通过多肽引导路线进行自组装。我们相信，本研究结果为自组装嵌段共聚体系的发展提供了一个新的概念。
Block copolymers have attracted much attention as potentially interesting building blocks for the development of novel nanostructured materials in recent years. Herein, we report a new type of self-assembling block copolymer with changeable polymer backbone structure, poly(Fmoc-Ser)ester-b-PSt, which was synthesized by combining the polycondensation of 9-fluorenylmethoxycarbonyl-serine (Fmoc-Ser) with the reversible addition–fragmentation chain transfer (RAFT) polymerization of styrene (St). This block copolymer showed the direct conversion of the backbone structure from polyester to polypeptide through a multiO,N-acyl migration triggered by base-induced deprotection of Fmoc groups in organic solvent. Such polymer-to-polymer conversion was found to occur quantitatively without decrease in degree of polymerization and to cause a drastic change in self-assembling property of the block copolymer. On the basis of several morphological analyses using FTIR spectroscopy, atomic force, and transmission and scanning electron microscopies, the resulting peptide block copolymer was found to self-assemble into a vesicle-like hollow nanosphere with relatively uniform diameter of ca. 300 nm in toluene. In this case, the peptide block generated from polyester formed β-sheet structure, indicating the self-assembly via peptide-guided route. We believe the findings presented in this study offer a new concept for the development of self-assembling block copolymer system.