Multicomponent Block Copolymers as Precursors to Functional Nanoporous Materials

技术摘要：嵌段共聚物是含有多个共价连接的聚合物链段的杂化大分子。这些材料可以在纳米尺度上自组装，并可以采用各种有序形态。对于AB两嵌段共聚物，A组分在B组分的基质中六方堆积的纳米圆柱体是一种常见的形态。对于ABC三嵌段三元共聚物，在C组分的基质中普遍存在A组分的圆柱体被B组分的外壳包围的形态。在这两种情况下，A组分的选择性化学刻蚀都将导致具有以牺牲组分为模板的通道的纳米孔材料。这种使用脂肪族聚酯和聚醚作为可降解组分来合成纳米孔材料的方法是该项目的核心。旨在提高有序嵌段共聚物制得的纳米多孔材料的机械完整性的方法将被探索。这包括设计和开发高度缠绕、半结晶或热塑性弹性体的基质聚合物。这些工作将极大地扩展对纳米多孔塑料的机械性能的了解，并为这些材料的未来应用提供基础。此外，还将考察嵌段共聚物衍生的纳米多孔材料作为多相催化的高比表面积载体的使用。这些底物的可调性尤其值得注意，这将使我们能够详细了解这些材料如何作为负载型催化剂的介质，并将这些材料开发为实际的催化剂载体。负载型纳米粒子、简单的有机催化剂和更复杂的基于多肽的催化和酶将被探索用于各种催化和不对称转化。非技术摘要：多孔材料在非常广泛的技术应用中发现了用途。这些无处不在的有机和无机材料具有重要的商业价值，例如，在石油化工中用作催化剂，在生物技术中用作分离介质，在微电子中用作层间介质。这项工作的主要目标是设计、合成和开发具有广泛可调性能的新型聚合物(即塑料)纳米多孔材料(具有纳米大小的孔的多孔材料)。这项工作是由先进的纳米技术应用推动的，重点是揭示与这些新材料的化学和物理性能的合成和最终调整相关的基本原理。该提案中开发的材料最终将通过在分离(如水净化)和催化(即绿色化学)中的应用而产生社会效益。纳米多孔材料在这些方面的应用已有报道，这项研究将直接影响嵌段共聚物在这些应用中的应用。还将对参与该项目的研究人员进行广泛的聚合物科学培训，并将实施旨在向本科生和公众宣传基础研究重要性的具体战略。

TECHNICAL SUMMARY:Block copolymers are hybrid macromolecules that contain multiple, covalently connected polymer segments. These materials self-assemble on nanometer length scales and can adopt a variety of ordered morphologies. For AB diblock copolymers, hexagonally packed, nanoscopic cylinders of the A component in a matrix of the B component is a commonly observed morphology. For ABC triblock terpolymers, a morphology with cylinders of the A component, surrounded by a shell of the B component, in a matrix of the C component is prevalent. Selective chemical etching of the A component in both of the cases will lead to nanoporous materials with channels templated by the sacrificial component. This approach to the synthesis of nanoporous materials using aliphatic polyesters and polyethers as the degradable components is central to this project. Methods aimed at enhancing the mechanical integrity of nanoporous materials from ordered block copolymers will be explored. These include the design and development of matrix polymers that are either highly entangled, semi-crystalline, or thermoplastic elastomers. These efforts will significantly expand understanding of mechanical properties in nanoporous plastics and provide the basis for future applications of these materials. In addition, the use of block copolymer-derived nanoporous materials as high surface area supports for heterogeneous catalysis will be examined. The tunable nature of these substrates is particularly noteworthy and will enable both a detailed understanding of how these materials behave as media for supported catalysts and development of these materials as practical catalyst supports. Supported versions of nanoparticles, simple organocatalysts and more complex peptide based catalysis, and enzymes will be explored for a variety of catalytic and asymmetric transformations.NON-TECHNICAL SUMMARY:Porous materials have found utility in an extremely wide range of technological applications. These ubiquitous organic and inorganic materials are commercially important as, for example, catalysts in the petrochemical industry, separation media for biotechnology, and interlayer dielectrics for microelectronics. The principal objective of this work is to design, synthesize and develop new classes of polymeric (i.e., plastic) nanoporous materials (porous materials with nanometer sized pores) with wide-ranging, tunable properties. This work is motivated by advanced nanotechnological applications and will focus on uncovering fundamental principles associated with the synthesis and ultimate tuning of the chemical and physical properties of these novel materials. Materials developed in this proposal will ultimately lead to societal benefit through applications in separations (e.g., water purification) and catalysis (i.e., Green Chemistry). The use of nanoporous materials for these purposes has been reported, and this research will directly impact the utility of block copolymers in these applications. Broad polymer science training of the researchers working on this project will also result, and specific strategies aimed at communicating the importance of basic research to both undergraduate students and the public will be implemented.