固体表面介导的双亲分子聚集行为研究

We recently found that solid surface can induce structural transition of amphiphilic aggregates in bulk solution. Specially, we obtained stable vesicles formed from only one simple single-chain surfactant without any additives, which seems to be inconsistent with the current theory or knowledge of vesicles. Therefore, many essential questions concerning the nature of this phenomenon need to be studied.. In this project, solid surface-mediated structural transition behavior of amphiphilic aggregates in bulk solution will be investigated using different solid surfaces and amphiphiles as models, and the effects of various factors such as solid surface and amphiphilic features, pH, temperature, ionic strength and additives on the structural transition and aggregate (vesicle) properties will be examined. Especially, high resolution scanning tunneling microscopy (STM), frequency modulation atomic force microscopy (FM-AFM), and laser scanning confocal microscopy (LSCM) as well as aggregation-induced emission (AIE) amphiphiles will be used to in situ observe the micro-processes of the amphiphile aggregation at solid-liquid interfaces and the structural transition in bulk solution. In addition, molecular simulation will also be used to study, at the molecular level, the micro-processes, to reveal essential correlation between the surface aggregation of amphiphiles and the structural transition of the aggregates in bulk solution. The rules, mechanisms and control methods of the solid surface-mediated structural transition processes will be discussed. This work can help us to get a better insight into the interfacial phenomenon and amphiphilic aggregation behavior.

近期我们发现，固体表面可诱导体相溶液中双亲分子聚集体结构转化，特别是在无添加剂存在下获得了由单一简单单链表面活性剂形成的稳定囊泡，这似乎与现有囊泡认识相悖，因而相关的一些基本问题需要探索研究。. 本课题拟选取不同性质（化学组成、粗糙度或曲率、润湿性和电性等）的固体表面和不同类型（离子类型和分子结构）的双亲分子为模型，研究固体表面介导的体相溶液中聚集体结构转化行为，考察各种因素的影响及囊泡特性；采用高分辨扫描隧道显微镜、调频原子力显微镜和激光扫描共聚焦荧光显微镜技术及具“聚集诱导发光”特性的双亲分子，原位实时检测固-液界面的聚集状态及其结构转化过程；采用分子模拟技术，在分子水平上研究表面聚集体形成、迁移及在体相中结构演化过程。揭示表面聚集与体相聚集体结构转化的内在联系，探索“介导”规律及调控方法，阐释其机理等。以期加深对界面现象和双亲分子聚集行为的科学认识。

前期我们发现，固体表面可诱导体相溶液中双亲分子聚集体结构转化，特别是在无添加剂存在下获得了由单一简单单链表面活性剂形成的稳定囊泡，这似乎与现有囊泡认识相悖，因而相关的一些基本问题需要探索研究。. 本工作对固体表面介导双亲分子聚集行为进行了研究。构建了固-液界面酸-碱反应平衡、吸附平衡和表面活性剂聚集吸附平衡的“尺寸效应”模型，加深了对界面曲率与界面电性能和吸附相关性的认识。提出了“动态键合平衡”热力学模型，阐释了固-液界面吸附层结构（组成和厚度）与平衡吸附量间的内在联系。发现“脱水-再水化”（DH-RH）循环可促进简单单链双亲分子（STAs）单组分溶液的胶束-囊泡结构转化，并可获得纯囊泡体系（或囊泡为主的体系）。实验和分子模拟研究表明，STAs在固体表面可形成烷基链间具高度交叉结构的双分子膜，这是STAs囊泡形成与稳定的内在原因。另外，对STAs囊泡体系的稳定性、界面膜微粘度、微极性和渗透性等进行了研究。本工作加深了对界面现象和双亲分子聚集行为的认识。（已发表SCI收录论文25篇）