聚电解质-二茂铁表面活性剂的电化学可控自组装与电化学可控释放体系的构建

Ionic self-assembly of polyelectrolytes with oppositely charged surfactants in solution is an important field of the macromolecular self-assembly. However，few reports on the controlled self-assembly of polyelectrolytes with oppositely charged surfactants have been published up to now. In this project, a new approach to construction of polyelectrolyte-surfactant controlled self-assembly was proposed by introducing ferrocenyl surfactants with reversible redox activity as functional assembly blocks. The main goal is to establish the new electrochemically controlled self-assembly method of polyelectrolytes with oppositely charged ferrocenyl surfactants in solution by studying the aggregation behavior of ferrocenyl surfactants in duble-hydrophilic block polyelectrolyte solution and the effect of electrochemical redox on their aggregation and disaggregation in detail；The second goal is to demonstrate the principle and method of electrochemically controlled release based on the polyelectrolyte-ferrocenyl surfactant aggregates by investigating the effect of the aggregates on loading and electrochemically controlled release behavior of hydrophobic guest molecules. The project focuses on the combination of the controlled self-assembly and function assembly. The results promise to expand the application of ferrocenyl surfactants in the macromolecular self-assembly and enrich the tuned method of polyelectrolytes-surfactants self-assembly systems. The results would be useful for the development of electrochemically responsive functional self-assembly systems.

表面活性剂在聚电解质溶液中的离子自组装是大分子自组装的一个重要领域，但有关其可控自组装却鲜有报道。本项目提出了以具有可逆氧化还原活性的二茂铁表面活性剂作为功能基元来构建聚电解质-表面活性剂的可控自组装新思路。主要目标是通过研究二茂铁表面活性剂在嵌段聚电解质溶液中的聚集行为以及电化学氧化还原对聚集及解聚集行为的影响，建立新的基于嵌段聚电解质-二茂铁表面活性剂的电化学可控自组装与解组装方法；其次是通过系统研究嵌段聚电解质-二茂铁表面活性剂聚集体对疏水客体分子的装载与电化学控释性，揭示这种自组装聚集体的电化学可控释放的原理与方法。本项目的特色是将可控自组装与功能组装相结合。研究结果将进一步拓展二茂铁表面活性剂组装基元在大分子可控自组装中的应用，丰富聚电解质-表面活性剂自组装体系的调控方法，同时也为发展新型电化学响应型功能自组装体系提供有益的借鉴。

首先我们合成了含二茂铁端基（Fe）的不同结构的多取代苯甲酸树形分子，将其与聚乙二醇单甲醚酯化制备了不同的树枝化两亲高分子。发现尾链数、聚乙二醇单甲醚的分子量对高分子在溶液中的聚集结构有显著的影响，这些高分子在溶液中可组装成不同的纳米结构如球型胶束、蠕虫胶束和囊泡等，也能通过氧化还原反应实现可逆的自组装与解组装和罗丹明6G（R6G）模型分子的可控释放；其次，我们合成了一系列不同聚合度的二茂铁基两亲嵌段共聚物。发现在相同摩尔浓度和氧化还原电压下，二茂铁基两亲嵌段共聚物在水中的临界聚集浓度越大、亲水性越大，其电化学氧化还原速率也越快。利用其还原态和氧化态的临界聚集浓度差，成功实现了其在溶液中的电化学氧化还原可控自组装与解组装。另外，通过活性自由基聚合方法合成了聚乙二醇-聚丙烯酸双亲水嵌段共聚物PEG113-b-PAA30，通过与二茂铁表面活性剂FTMA静电复合制备了超两亲嵌段共聚物 PEG113-b-PAA30/FTMA， 实现了其在溶液中的电化学氧化还原可控自组装和解组装，并将这种电化学可控自组装方法成功应用到电化学可控释放领域。最后，我们合成了一系列含二茂铁端基的Percec型树型分子功能化的疏水改性乙氧化聚氨酯（HEUR）模型高分子Fc-HEUR、Fc2-HEUR和Fc3-HEUR。这些高分子在水溶液中能形成氧化还原响应的可控自组装以及β-环糊精（β-CD）包合引起的可控自组装。发现氧化还原反应和β-CD的包合作用导致溶液的胶束转变和网络重排不仅影响网络连接性而且会改变溶液的松弛行为。上述成果对高分子可控自组装体系的构建、环境响应型功能高分子材料的制备与应用有一定意义。