熵焓控制的嵌段共聚物与纳米立方体的共组装

Block copolymer nanocomposites become more and more useful in many fields recently. However, there is still a challenge in tuning the coassembly of block copolymers and nanoscale building blocks. This project aims to provide insight of the bulk coassembly of block copolymers and anisotropic nanocubes by adjusting entropy and enthalpy contributions, and it could be achieved by carefully choosing thermodynamic parameters such as the protecting layers of the nanocubes and the molecular weight of block copolymer. Nanoparticle arrays with multiple assembly styles, different position-selectivities, ordered spacing arrangement and high loading could be obtained through precise tailoring the mixing enthalpy, translational entropy, conformational entropy and orientational entropy of the hybrid systems. The project may not only improve the understanding of this kind of coassembly behaviors, but also act as a model for study of the coassembly of block copolymers and inorganic nanomaterials. In addition, researches focused on the structure–property relationships of polymer based organic-inorganic nanocomposites would be benefited from this project.

近年来，基于嵌段共聚物的纳米复合材料在诸多领域发挥着越来越重要作用，而如何有效调控嵌段共聚物与各种各样的纳米构筑单元的共组装仍然面临着挑战。本项目拟以嵌段共聚物与各向异性纳米立方体在本体中的共组装为研究对象，从体系的热力学角度出发，通过选择不同的相关参量如纳米立方体的表面保护分子层及嵌段共聚物的分子量等等实现对体系熵焓的控制。在精确调节体系中混合焓、平移熵、构象熵及取向熵等的情况下，获得纳米粒子的组装方式的多样化、组装位置的选择性、空间排布的有序化及高负载量。这些除了能丰富人们对于这类共组装体系相行为的认识，也可作为一类本体模型体系为嵌段共聚物与无机纳米材料的共组装提供思路、理论和实验依据，助力于高分子相关的有机-无机纳米复合材料的结构与性能的研究进展。

通过与纳米粒子进行组装，高分子纳米复合材料能够展现出与传统高分子材料不同的光学、电学和力学等性质，也因此广泛应用于生命、能源、光电和环境等领域。在课题研究过程中，我们掌握了将纳米立方体用高分子改性并有效组装于嵌段共聚物中的关键技术，总结了高分子膜上这种各向异性金属纳米粒子的负载规律，发现控制体系的熵变能够诱导纳米立方体组装于特定相区中，但是无法通过改变构象熵影响嵌段共聚物微相分离结构，而高含量纳米粒子的组装则会导致宏观相分离的产生；此外，通过焓变的引入，我们将纳米立方体组装于不同的高分子膜上，可以实现纳米立方体的组装方式的多样化，系统研究了纳米立方体的负载量与形成的纳米复合材料的催化性能之间的联系，获得了具有不同微观结构和潜在应用价值的高分子纳米复合材料。本课题的研究结果能够对类似高分子-纳米粒子组装体系的结构与性能的研究产生积极的推动作用。