基于聚电解质的含氟两亲性光固化涂层的构建及其防雾、防霜性能研究

Fogging or frosting formation due to changes in temperature and humidity on optical instruments or photovoltaic glass may cause image distortion and reduction of light-to-electric conversion efficiency. Traditional antifogging methods by heating or sprayed chemicals can cause energy consumptions or environment pollutions. Therefore, the study of effective antifogging and frost-resisting coatings is of great importance. Water-absorbing coatings can imbibe water molecules from the surrounding vapor, thus preventing the formation of water droplets on the coating surface. Frost-resisting properties can be improved by increasing the bound water content or decreasing freezing/melting temperature of water. . In the present project, we propose to prepare UV-curable coatings composed of amphiphilic polyelectrolyte copolymers and poly(ethylene glycol) (PEG) for the purpose of antifogging and frost-resisting applications. The polyelectrolyte copolymers will be synthesized via free radical polymerization of trifluoethyl methacrylate, allyl methacrylate with different types of electrolytes, such as 3-sulfopropyl methacrylate potassium salt or [2-(methacryloyloxy)ethyl]-trimethylammonium chloride or [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide. The counterions of the polyelectrolyte copolymers will be exchanged by various types of ions. . A series of UV-curable copolymer coatings with different compositions will be prepared by using the polyelectrolyte copolymers and PEG dimethacrylate. The glass substrate will be modified by 3-(methacryloxypropyl)-trimethoxysilane to improve coating/substrate adhesion. The wettability, antifogging and frost-resisting properties of UV-curable copolymer coatings will be studied. The effects of different electrolytes and ions in the copolymers and the coating composition on the water state and the antifogging and frost-resisting properties will be investigated. It is supposed that this research will provide fundamentals and new strategies for preparation of novel coatings for antifogging and frost-resisting applications.

光学仪器或太阳能设备面板等表面的结雾和冻霜现象，给仪器使用和光能利用造成很大影响。传统加热或喷洒防雾剂方法存在能耗高、环境污染等问题，因此研究高效防雾、防霜涂层材料非常必要。吸水性涂层可将空气中的水分子吸入到涂层内部而在表面不发生结雾，提高吸水性涂层中结合水含量或降低水的冰(熔)点有利于提高涂层防霜性能。本项目拟从共聚物化学结构与涂层组成角度出发，以不同种类的电解质单体(阴离子型、阳离子型和磺酸甜菜碱两性离子型)、甲基丙烯酸三氟乙酯和甲基丙烯酸烯丙酯等为原料，通过自由基聚合法合成两亲性聚电解质无规共聚物，与聚乙二醇二甲基丙烯酸酯交联，制备一系列不同共聚物化学结构和涂层组成的光固化涂层。用离子交换方法改变离子类型，重点研究共聚物中亲疏水组成比例、电解质及离子种类、涂层组成与涂层中水与共聚物的结合状态对防雾、防霜性能的影响，为制备新型防雾、防霜涂层材料提供新思路和新方法。

透明基材表面起雾、结霜现象会造成材料表面的透光率降低，给人们的生产生活带来诸多不便，甚至造成安全隐患。吸水性防雾涂层可将基材表面水分子吸入到涂层内部而在表面不发生结雾。聚电解质材料可与水分子之间产生较强的静电作用，有利于提高涂层的吸水性，同时其较强的作用力也有利于降低水的冰点，使涂层具有防霜、防冰的功能。本文以不同种类的电解质单体(阴离子型、阳离子型和磺酸甜菜碱两性离子型)和甲基丙烯酸二甲氨基乙酯为亲水性单体，以含氟丙烯酸酯和多面体低聚倍半硅氧烷为疏水性单体，通过活性自由基聚合方法合成了两亲性聚电解质共聚物，并与二甲基丙烯酸乙二醇酯共混，通过紫外光交联固化制备涂层。所制备的共聚物涂层具有优良的防雾性能，并能够在-5℃、相对湿度为50%条件下保持45分钟不结霜。采用差示扫描量热法、拉曼光谱法和低场核磁共振法对共聚物涂层与水分子间作用力进行了分析，探究了涂层防雾、防霜功能机理。建立了共聚物分子量、亲疏水组成比例、电解质种类、涂层组成成分、交联剂含量等因素与涂层表面润湿性、内部水的状态以及防雾、防霜性能之间的关系。研究表明涂层中的结合水和不冻结结合水及分子间的相互作用是影响防雾、防霜性能的主要因素。通过本项研究为制备新型防雾、防霜涂层材料提供了新思路和新方法。