蠕虫状胶束对飞机防冰液醇水溶液流变特性影响机理研究

Thickened anti-icing fluid for aircraft is composed of thickener, wetting agent, and corrosion inhibitor, etc., solubilized in the mixed solvent of glycol and water. It plays an important role in guaranteeing the safe flight of aircraft in winter. The high viscosity and rheological properties of thickener are key factors influencing the anti-icing and aerodynamic performances. Wormlike micelles can function as thickener and rheology-control agents in aqueous systems, much like polymers by constructing a transient network. It is the first time to study wormlike micelles in the glycol-water medium and introduce their application in aircraft anti-icing field. By investigating the influences of surfactant structure and solvent polarity on micellar morphology, it is attempted to acquire the driving force for surfactant aggregation and the mechanism of micellar self-assembly, which is helpful to provide guides to prepare surfactants with need characters. Base on series of target surfactants, the optimum wormlike micelle system can be selected in glycol-water aiming for the excellent viscosifying and shear-thinning behaviors. The study and introduction of wormlike micelles into aircraft anti-icing field will not only overcome defect such as gel residues in the present thickened anti-icing fluid but also develop a new prospect for exploiting novel aircraft anti-icing fluid. The work will also bring considerable insight into the self-assembly of wormlike micelles in glycol-water.

增稠型飞机防冰液是由增稠剂、润湿剂和缓蚀剂等组成的醇水混合溶液，在保障冰雪气候下的飞机安全飞行中起着重要作用。增稠剂提供的黏度和流变特性是影响飞机防冰液防冰和低温空气动力学性能的关键因素。针对防冰液醇水混合体系，研究、设计并构筑具有增稠、小分子自组装结构、剪切变稀和松弛时间短等特性的蠕虫状胶束尚属首次。本项目通过流变学、电镜和光散射等技术，考察表面活性剂的结构以及溶剂极性对胶束形态的影响，探寻醇水混合溶液中表面活性剂的聚集机理；制备具有特征结构的表面活性剂，实现并优化醇水体系中蠕虫状胶束的增稠和剪切流变特性。研究蠕虫状胶束在防冰液醇水溶液中的增稠和流变行为，不仅为解决增稠型防冰液目前所面临的水合凝胶问题，也为开发新型飞机防冰液提供了全新思路和方向，是醇水溶液中胶束自组装领域的有益探索，具有重要的理论意义和应用价值，有助于提高我国冬季航空运营安全的保障水平，补充和发展胶束领域相关理论。

本研究将具有小分子自组装结构的蠕虫状胶束引入除防冰液领域。首先以常规商品化表面活性剂为研究对象，采用表面张力测试、电导率测试、相行为观察等手段考察了制约其溶解和聚集的因素。研究结果表明短链表面活性剂、电解质或醇的加入可以实现对表面活性剂溶解性的调控；加入乙二醇或丙二醇明显降低表面活性剂的表面活性；在水醇体系，非离子表面活性剂的头基变化对其表面活性影响甚微。进一步采用流变测试技术考察了表面活性剂在水和醇水混合溶剂中的自组装行为。表面活性剂的链长是制约其在水溶液中聚集行为的主要因素，NaOEr比NaOA更易聚集形成蠕虫状胶束。根据在水溶液中的研究基础，制备了具有特征结构的表面活性剂。醇水体系中有机盐的诱导下，该表面活性剂在极低的浓度下形成了具有粘弹性的蠕虫状胶束，高醇含量下溶液的表观粘度受到削弱，丙二醇比乙二醇对胶束的破坏作用更强。本项目首次研究蠕虫状胶束在低温（-20～0℃）区域的构筑和流变行为。在低温区醇水体系中，极低浓度的表面活性剂便形成具有较强粘弹性的蠕虫状胶束，粘度随温度降低而规律性增加，符合阿伦尼乌斯方程。温度升高和醇含量增加都会降低溶剂的介电常数，同时削弱表面活性剂分子的疏溶剂作用，两种效果都不利于促进表面活性剂分子的相互作用。本研究将表面活性剂的自组装行为拓展到低温领域的醇水体系，探讨了制约表面活性剂聚集行为的内在动力因素，丰富了自组装行为的知识，为蠕虫状胶束在除防冰领域的应用提供技术支持和有益的参考。