压缩气体诱导聚电解质刷的聚集及其微环境的性能和应用研究

Due to the unique structure and tuneable surface properties, polyelectrolyte brushes (PB) provide an ideal model system for the study on environment-stimuli responsive materials and they are a field of great importance to both pure and applied sciences. However, how to recover the costly PB is the bottleneck which has restricted the development. This project employs compressed gas whose unique anti-solvent effect will regulate solvent strength of system. In other words, it will change the micro environment of PB and induce the aggregation and precipitation of absorbed substance, such as nano-metal particles and protein, and PB respectively. The innovation point is inputting the anti-solvent effect of the compressed gas into PB which an environment-stimuli responsive material and then get the smooth recovery of PB well. First of all, an apparatus to determine the phase behaviour of compressed gas-polymer solution system will be constructed. The effect of compressed CO2 or other gas on the phase behaviour of different polyelectrolyte brushes solutions will be studied. Secondly, different techniques, such as UV-vis, FTIR, and SAXS will be used to study the properties and micro-structure of PB system while aggregation with the pressure. The possible mechanism will be proposed after the phase behaviour and micro-environment study. On the base of the previous research, we will focus on the applications of this novel method of PB recovery including: the treatment of wastewater contains phenol and heavy metal ion, heavy metal catalytic reaction, the photo-catalysis reaction and enzyme catalytic reaction. This novel method will provide valuable suggestion for how to recovery costly PB and extend the application of PB in catalytic, environmental protection et.al.

聚电解质刷由于其特殊结构可极大地改变固体表面性能从而可对所处环境做出快速响应，因此成为近年来的高分子领域的研究热点。但如何有效分离回收价格昂贵的聚电解质刷却成为制约该技术发展的瓶颈。本项目拟用压缩气体独特的抗溶剂效应调节体系的溶剂化强度，从而改变聚电解质刷的微环境导致其和被吸附物的分级聚集和沉淀，并以此为创新点分别回收被吸附物质和聚电解质刷。首先研究不同的高压气体对不同组成的聚电解质刷体系的相态影响；随后辅之以紫外，红外，荧光光谱，小角X射线散射等多种表征手段对压缩气体诱导聚电解质刷溶液的聚集过程，性质与微观结构进行研究，并提出相应机理；最后在此基础上，探索其在含有酚类污水处理，重金属催化反应以及生物酶催化方面的应用。期待本项目的成功实施将为探索聚电解质刷在催化、环保和材料等领域的应用提供理论基础和实验技术依据。

纳米球形聚电解质刷(SPB)是一种聚合物链接枝在胶体颗粒表面，具有核壳结构的高分子材料，由于其独特的结构和性能，在诸多领域有潜在的应用价值。但是，由于它不易从溶液中分离，从而成为制约该技术发展的瓶颈。压缩二氧化碳 （CO2）具有独特的抗溶剂效应，即能够调控溶液中溶剂的溶剂化能力而完成降压分离溶质。本课题主要利用压缩CO2的抗溶剂效应来调节纳米球形聚电解质刷溶液的性能，主要有以下三部分的工作：.1..首先完成了聚电解质刷的微相分离和回收。首先研究了SPB-CO2-溶剂三元体系的相行为，考察了温度，粒径和固含量对体系浊点压力的影响。结果表明，通过控制压力可以对SPB进行沉降分离和回收。通过压力调节完成多次循环过程后，SPB性质依然能够几乎与初始状态保持一致。然后在SPB上原位生成银纳米粒子或者负载蛋白质，通过CO2调节溶液的性能，使银纳米粒子与SPB分级沉降，回收得到粒径分布均匀的银纳米粒子或蛋白质。.2..在第一部分工作的基础上，利用SPB作为吸附剂通过静电作用选择性吸附染料，并利用压缩CO2的抗溶剂效应诱导SPB和被吸附物进行微相分离，进而利用盐效应对SPB进行回收，同时对吸附过程进行了热力学方面的研究。发现SPB对染料的吸附过程遵循二阶动力学模型， Weber's粒间扩散模型拟合说明吸附过程并不只是受粒间扩散控制，符合Freundlich模型，同时SPB对染料而言是优秀的吸附剂。.3..此外，我们制备了一种新型具有CO2刺激响应性的SPB。它兼具pH、盐离子敏感以及温敏性，属于多重响应性聚合物。系统性地研究了pH值、盐离子以及温度对它吸附蛋白质效果的影响；并发现利用CO2/N2作为新型的绿色刺激源，可逆脱附-吸附蛋白质，从而避免盐浓度聚集；除此之外将其用于稳定Pickering乳液，可使用CO2有效调节其乳液性能。.综上所述，该项目的顺利结题不仅能对价格昂贵的SPB提供简单有效的分离回收手段，同时将为探索聚电解质刷在催化、水处理和材料等领域的应用提供理论基础和实验技术依据。