调控两亲性构筑可控乳液

Hierarchical polymer materials with porous structures, which possess advantages of low density and high specific surface area, have shown great promise for the applications in the areas of biotechnology, pharmacotherapy, material science, sensors, catalysis, oil-water separation and environmental engineering. Among methods for the preparation of hierarchical polymer materials, the emulsion-based technology is relatively efficient and economically efficient. More importantly, the emulsion method can be applied to mass production with the ease of loading function, opening a fascinating avenue for preparing functional materials with desirable micro/nano structures. However, the removal of surfactants and control of phase inversion as well as separation are still challenging in emulsion systems. To be specific, the control of "premulsion” in emulsification process and “proemulsion” in solvent evaporation process with the help of interfacially active substances is critical for the fabrication of polymer materials with hierarchical topologies. Enormous interests are raised to amphiphilic polymers that can serve as emulsion matrix as well as interfacial stabilizer for controllable emulsions. In this project, we propose to develop “one-step” emulsions without the use of surfactants. Polymers with control over amphiphilicity are expected to tailor the phase inversion during emulsification and phase separation during solvent evaporation in addition to acting as emulsion matrix. Instead of complicated synthesis, supramolecular route and external stimulation are preferred for tuning polymer amphiphilicity. To realize their full potential, we plan to introduce functional agents or moieties into the hierarchical polymer materials.

具有分级结构的多孔聚合物材料以其独特的优势在生物、医药、材料、环境等领域有着十分广阔的应用前景。基于乳液技术制备聚合物分级结构材料已成为当前制备分级材料的一个重要方法。然而，乳液技术在实际应用过程中面临着表面活性剂的去除和乳液可控性的提高等关键挑战。乳液的可控性在制备乳液时“前乳液”的乳化过程和“后乳液”的溶剂挥发过程中具体体现，其中界面活性物质扮演着主导性的角色。选取既可以作为乳液基材，又可以作为乳化剂和稳定剂的两亲性聚合物是一种快速并有效地制备可控乳液的新策略。本项目从调控聚合物两亲性的角度出发，针对“前乳液”和“后乳液”不同过程的调控，设计并合成可通过超分子相互作用或者外界刺激响应改变两亲性的几类聚合物，进一步影响并操纵乳液的相反转和相分离行为，实现在不添加表面活性剂的前提下“一步法”构筑可控复杂乳液体系，并获得聚合物分级结构材料。

乳液是两种或两种以上不相溶液体在借助乳化剂乳化作用下形成动力学稳定的混合体系，被广泛应用于石油化工、涂层涂料、食品、化妆品、生物分析和微纳米材料制备等诸多领域，因此对于乳液特性的探索和新型乳化剂的开发是科学研究的热点。二十一世纪以来，乳液液滴的可控性被初步揭开，利用智能化设计的乳化剂可以通过调控两亲性来实现包括水包油型（O/W）、油包水型（W/O）、水包油包水型（W/O/W）和油包水包油型（O/W/O）的四大类型乳液相互转换的可控乳液制备。利用构筑的可控乳液模板进行材料制备，不仅可以极大地降低成本和简化制备过程，而且可以赋予材料特殊的结构和功能。本项目通过设计和开发新型乳化剂，成功实现了调控乳化剂两亲性构筑可控乳液的目的，进而合成了多种微米颗粒和宏观块状的功能材料。除了在乳化剂设计方面的工作，我们还开发了新型单分散液滴生成技术，降低了单分散微液滴和单分散微米颗粒制备的成本和技术门槛。项目具体内容和研究成果如下：（1）设计智能化两亲性可调控的单分子型和微米颗粒型乳化剂，提出了利用气体分子作用、超分子作用和氧化还原反应途径调控两亲性的创新机理机制，实现各种乳液形态之间的可控转换，极大地丰富了可控乳液的理论架构。（2）以可控乳液为模板，合成了一系列多孔微米颗粒、特殊形状微米颗粒和大块微孔材料，并将具有光热转换特性的功能材料应用于疾病治疗、能源利用、电子传感和环境保护领域。（3）设计低成本和便捷的单分散液滴生成技术，提出相应的技术概要和技术理论，成功制备了单分散微米颗粒，并将其应用于生物分析和乳液转变过程分析。