形状可控刺激响应微凝胶的电化学聚合制备及溶液性质研究

Stimuli-responsive microgels have great potential in the fabrication of smart-feedback systems on the basis of continuously sensing changes in their environments. While the molecular design and size/structure control on stimuli-responsive microgels have been hot tops, two issues of particular relevance to such microgels, including the non-spherical shape control and its impacts on the solution properties, are barely referred and still remain challenges. To address these issues, in this project, we aim to exploit electrochemistry as an unique catalytic or initiate method to induce polymerization, so as to synthesize temperature, pH value, or glucose responsive microgels of controllable non-spherical shape, which then will be manipulated through stimuli-responsive shape-switching. Next, we will investigate the volume phase transition behavior and dynamics of those microgels in response to the change in temperature, pH value, or glucose concentration, respectively, where we can get the feedback for optimizing the synthesis of the microgels, towards the design of microgels with controllable responsive characteristics and more importantly, towards the understanding on the impact of the shape on the structure-property relationships among stimuli-recognition, volume phase transition and optical response. Moreover, as a primary linkage between foundational research and practical application, we would like to extend our research to the synthesis of functional microgels, which may be used for stimuli-to-optical signal conversation or regulate transport of pharmaceuticals. Our results should underscore the vast potential of stimuli-responsive microgel for the fabrication of smart systems that can be used in biosensing, diagnosis and therapy.

刺激响应微凝胶极有望用于构建可持续感知环境变化并输出反馈的智能反馈型系统。针对当前刺激响应微凝胶存在的两个挑战性问题（刺激响应微凝胶的分子设计、粒径/结构控制已成热点，但微凝胶研究中的纳微米科学基本问题——颗粒形状控制的机制及方法——相对缺乏探索且尚无令人满意的答案；尚无研究报道刺激响应微凝胶的形状对其溶液性质的影响），本项目拟通过电化学催化或引发聚合，制备非球形等形状可控的温度、pH值或葡萄糖响应微凝胶，并在制得非球形微凝胶后通过刺激响应形状转变再次调控形状；然后从宏观、微观、分子水平三个层次认识微凝胶形状对体积相转变等溶液性质的影响规律，揭示从识别到体积相转变再到光学响应的内在机制。作为基础研究通往实际应用的链接，本项目还将尝试构建并研究可在单颗粒中主要突出刺激——光学信号定量转换、药物控释等功能的微凝胶，为从高分子化学与物理角度设计生物学功能导向智能反馈型系统的最终目标提供科学依据。

针对当前刺激响应微凝胶存在的两个挑战性问题（刺激响应微凝胶的分子设计、粒径/结构控制已成热点，但微凝胶研究中的纳微米科学基本问题——颗粒形状控制的机制及方法——相对缺乏探索且尚无令人满意的答案；尚无研究报道刺激响应微凝胶的形状对其溶液性质的影响），本项目主要工作在于研究形状可控刺激响应微凝胶的电化学聚合制备及溶液性质。本项目不仅按研究计划进行，还根据解决问题的需要适当拓展研究，结合电化学等相关学科的最新发展，通过采用电化学催化或引发聚合等体系，制备非球形等形状可控的温度、pH值、葡萄糖等响应微凝胶，然后从宏观、微观、分子水平三个层次认识微凝胶形状对体积相转变等溶液性质的影响规律，并作为基础研究通往实际应用的链接，尝试构建并研究可在单颗粒中主要突出刺激——光学信号定量转换、物质控制输运等功能的微凝胶。通过上述研究，我们至少在以下三个方面取得了进展：（1）形状可控刺激响应微凝胶的电化学聚合制备等相关合成方法探索，此部分内容为本项目的核心，其中着重发展了直接引发聚合法、间接引发聚合法两种合成途径，并通过调控方波电位等条件来深入探究微凝胶形成机理；（2）形状可控刺激响应微凝胶的刺激响应形状转变研究；（3）形状可控刺激响应微凝胶的溶液性质研究。为便于体现研究思路的连贯性，我们将换个角度、选取代表性成果进行具体介绍：A）具有立方体形状的温度响应微凝胶的合成及溶液性质研究；B）具有环形形状的pH值等响应微凝胶的合成及溶液性质研究；C）非球形的葡萄糖响应微凝胶的合成及溶液性质研究。这些结果体现了形状可控刺激响应性高分子微凝胶的设计制备、溶液性质及其应用，为从高分子化学与物理角度设计功能导向自我反馈型智能系统提供科学依据，也为理解关键问题——纳微结构与材料性能的关系——提供有价值的视角。