基于CVD含氟聚合物镀层的超疏油自清洁表面研究

Current fabrication methods of superoleophobic, self-cleaning surfaces can be categorized into solution-based and vapor-based schemes. However, the solution-based methods can cause structural and compositional damages to solvent- or thermal-sensitive substrate materials, or materials with fragile micro- and nanostructures, while most vapor-based methods rely on the high energy introduced during the deposition process, such as plasma, which leads to the disruption of the stoichiometric control and functionality of the fluoride groups. This work proposes the use of a novel initiated chemical vapor deposition (iCVD) method, which employs a mild and controllable process to achieve superoleophobic fluorinated polymer coatings that are suitable for most substrate materials. By precisely designing the vertical structure of the coating, we will optimize the stability, durability and surface functionality of the coatings. A hierarchical surface morphology will be constructed by adopting a combinatorial method of templated patterning and surface grafting. We will investigate the impact of the side chain length of the fluorinated polymers, different deposition conditions and deposition techniques on the crystallinity, surface morphology, and surface energy of the synthesized polymer coatings. We expect the implement of this research will help us better understand the mechanism of iCVD-based synthesis of fluorinated polymers, further advance the applications of the hybrid grafting technique in fabricating functional polymer coatings, and establish a novel fabrication scheme towards superoleophobic, self-cleaning surfaces that are potentially applicable for industrial use.

现有的超疏油自清洁表面制备技术主要包括液相法和高能气相法。前者存在着溶剂易损伤部分基底材料的表面形貌与结构等局限性，而后者则不易对所需官能团的化学组分计量与功能性达到有效的控制。本项目拟采用一种新型的引发式化学气相沉积（iCVD）方法，利用该技术条件温和、干式镀膜、过程可控的优点，制备适用于绝大部分基底材料的含氟聚合物超疏油镀层，通过镀层的纵向结构设计优化膜基结合力、薄膜稳定性与表面功能性，通过模板法与复合接枝法的结合单步实现表面的微纳多级形貌构建，并探索不同侧链长度与沉积技术对含氟聚合物镀层的表面形貌、晶体结构与表面能的影响。通过本项目的研究，可在机理上实现对iCVD沉积含氟聚合物过程更深层次的理解，进一步拓展与完善气相复合接枝技术在材料表面功能化上的应用，系统地建立一套新型的可望面向实际应用的超疏油自清洁表面制备技术体系。

超疏水超疏油表面在防水防腐、自清洁、防雾防结冰表面等领域有广泛的应用。目前超疏水超疏油表面的制备往往需要两步进行，即制备低表面能涂层再在涂层上进行微纳形貌构建，或在表面上先构筑微纳形貌再对其进行表面改性。这两种制备策略均需要较繁琐的步骤。本项目的实施实现了一种单步法气相制备超疏水超疏油表面的技术。该技术是基于iCVD方法，即通过在真空环境下引入引发剂与单体，并辅以热丝加热使得引发剂裂解，在基底表面将被吸附的自由基与单体聚合成膜。本项目中所研发的技术首先在基底表面沉积一层打底层，在此基础上引入过饱和的含氟聚合物单体气体，从而在基底表面形核并生长成为均匀排布的聚合物纳米垂直阵列。该技术打破了原有诸多超疏水超疏油表面制备方法中需要分两步实施的弊端，在同一个过程中同时实现了低表面能涂层的沉积与表面微纳形貌的构筑。同时该方法不需要使用任何溶剂，亦不需要使用高温高能条件，具有基底普适的特性，有望实现不同材料的超疏水超疏油表面改性。本项目的研究过程中还实现了一种抗生物吸附的生物医疗器械表面制备方法，将此涂层应用于医用导管后发现血液细胞在表面的粘附有了明显的减少。此技术有望实现生物材料、医疗器械表面的抗生物粘附与抗凝血涂层的制备。最后，本项目中研发的聚合物纳米垂直阵列结构气相制备方法对聚合物纳米材料的制备开辟了一条新的路径。