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Aqueous reversible addition-fragmentation chain transfer polymerization of functional monomers and their incorporation into stimuli-responsive, amphiphilic block copolymers.

机译：官能单体的水可逆加成-断裂链转移聚合反应，以及将其掺入刺激反应性的两亲嵌段共聚物中。

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摘要

Reversible addition--fragmentation chain transfer (RAFT) is arguably the most versatile living radical polymerization technique in terms of the reaction conditions and monomer selection. Since the introduction of RAFT in 1998. McCormick and coworkers have employed the RAFT process to synthesize a wide range of water soluble (co)polymers with predetermined molecular weights, low polydispersities, and advanced architectures. However the controlled polymerization of important monomers, such as unprotected, chiral, amino acid based monomers, directly in water has yet to be reported. The incorporation of these monomers into stimuli-responsive block copolymers will create novel polymer systems that can be reversibly "locked" under facile conditions and have potential applications in sequestration and targeted delivery. Additionally, the controlled synthesis of (co)polymers based on chiral, amino acids directly in water can now be achieved and their chiroptical behavior investigated. The overall goal of this research is to utilize the RAFT process for the polymerization of chiral, amino acid based monomers directly in water, to investigate the self-assembly behavior of stimuli-responsive block copolymers containing an amino acid based block, and to investigate the chiroptical properties of enantiomeric (co)polymers based on the chiral, amino acid based monomers.; This work may be divided into four sections. The first section concerns the first successful RAFT polymerization of an unprotected amino acid based monomer directly in water and its incorporation into thermally responsive block copolymers. N-acryloyl L-alanine (ALAL) ( 48) was synthesized and its polymerization behavior in the presence of the dithioester CTP (64) and the trithiocarbonate EMP (67) was investigated. Block copolymers containing a hydrophilic block of DMA ( 58), a cross-linkable block of ALAL ( 48), and a thermally-responsive block of NIPAM ( 59) were subsequently synthesized, and the aqueous self-assembly behavior was investigated.; The second section expands on the aqueous RAFT polymerization of an unprotected amino acid based monomer and its incorporation into dual responsive block copolymers. N-acryloyl L-valine (AVAL) ( 50) was synthesized, and its polymerization behavior mediated by EMP (67) at both 30°C and 70°C was investigated. Block copolymers containing a hydrophilic block of DMA ( 58) and a statistical block of the thermally-responsive monomer NIPAM (59) and the pH responsive monomer AVAL (50) were synthesized, and their aqueous self-assembly behavior was investigated.; In the third section, the chiroptical properties of amino acid based (co)polymers were investigated. Chiral homo- and block copolymers based on the enantiomeric monomers ALAL (48) and N-acryloyl D-alanine (AVAL) (49) were prepared directly in water via RAFT polymerization. Enantiomeric homopolymers, block copolymers, and a statistical copolymer were synthesized, and the chiroptical activity of these biomimetic polymers and their analogous model compounds was investigated.; The fourth section details work done in collaboration with Dr. Yuting Li and concerns the utilization of RAFT for the preparation of shell cross-linked micelles for potential applications in sequestration and targeted delivery. Thermally responsive micelles based on poly (ethylene oxide)-block-[( N,N-dimethylacrylamide)-stat-(N-acryloxy succinimide)]-block-(N-isopropyl acrylamide) triblock copolymer are synthesized and subsequently shell crosslinked with ethylenediamine or cystamine. When cystamine is used, fully reversible SCL micelles are formed.
机译：就反应条件和单体选择而言，可逆加成-断裂链转移（RAFT）可以说是最通用的活性自由基聚合技术。自1998年引入RAFT以来，McCormick及其同事采用RAFT工艺来合成各种具有预定分子量，低​​多分散性和先进结构的水溶性（共）聚合物。然而，重要的单体，例如未保护的，手性的，基于氨基酸的单体直接在水中的受控聚合尚未有报道。将这些单体掺入刺激反应性嵌段共聚物中将产生新颖的聚合物体系，该体系可以在容易的条件下可逆地“锁定”，并且在螯合和靶向递送中具有潜在的应用。此外，现在可以直接在水中实现基于手性氨基酸的（共）聚合物的受控合成，并研究其手性行为。这项研究的总体目标是利用RAFT方法直接在水中聚合手性，氨基酸基单体，以研究含有氨基酸基嵌段的刺激反应性嵌段共聚物的自组装行为，并研究基于手性氨基酸基单体的对映体（共）聚合物的手性。这项工作可以分为四个部分。第一部分涉及未保护的基于氨基酸的单体直接在水中的首次成功的RAFT聚合，并将其掺入热响应性嵌段共聚物中。合成了N-丙烯酰基L-丙氨酸（ALAL）（48），并研究了其在二硫代酯CTP（64）和三硫代碳酸酯EMP（67）存在下的聚合行为。随后合成了包含DMA亲水嵌段（58），ALAL可交联嵌段（48）和NIPAM热响应嵌段（59）的嵌段共聚物，并研究了其水自组装行为。第二部分扩展了未保护的基于氨基酸的单体的水性RAFT聚合反应，以及将其引入双反应型嵌段共聚物中的过程。合成了N-丙烯酰基L-缬氨酸（AVAL）（50），并研究了其在30℃和70℃下由EMP（67）介导的聚合行为。合成了包含DMA亲水嵌段（58）和热响应性单体NIPAM（59）和pH响应性单体AVAL（50）的统计嵌段的嵌段共聚物，并研究了它们的水自组装行为。在第三部分中，研究了氨基酸基（共）聚合物的手性。通过RAFT聚合直接在水中制备基于对映体单体ALAL（48）和N-丙烯酰基D-丙氨酸（AVAL）（49）的手性均聚物和嵌段共聚物。合成对映异构均聚物，嵌段共聚物和统计共聚物，并研究了这些仿生聚合物及其类似模型化合物的手性。第四部分详细介绍了与Yuting Li博士合作完成的工作，并讨论了利用RAFT制备壳交联胶束的可能性，这些螯合物可用于螯合和靶向递送。合成了基于聚（环氧乙烷）-嵌段-[（（N，N-二甲基丙烯酰胺）-stat-（N-丙烯氧基丁二酰亚胺）]-嵌段-（N-异丙基丙烯酰胺）三嵌段共聚物的热响应胶束，然后将其与乙二胺进行壳交联或胱胺使用胱胺时，会形成完全可逆的SCL胶束。

著录项

  • 作者

    Lokitz, Bradley Steward.;

  • 作者单位

    The University of Southern Mississippi.;

  • 授予单位 The University of Southern Mississippi.;
  • 学科 Chemistry Polymer.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 189 p.
  • 总页数 189
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 高分子化学（高聚物）;
  • 关键词

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