类金刚石薄膜表面润湿调控研究综述

Review on Surface Wettability Regulation of Diamond-like Carbon Films

表面具有特殊润湿性特别是超疏水性的类金刚石薄膜,可满足在极端服役环境下(比如雨雪、潮湿环境中或者人体组织内)智能界面材料表面改性的需求。概述了类金刚石薄膜的生产工艺和性能优势及制备方法,介绍了具有特殊润湿性,特别是超疏水性的类金刚石薄膜的应用背景,同时提出了类金刚石薄膜表面润湿调控在理论和技术上的限制。在此基础上,阐述了类金刚石薄膜表面本征润湿性及与微观结构(包括杂化状态和短程或中程有序相团簇结构)间的关系。同时,基于经典的Wenzel和Cassie润湿理论,从表面化学组成和粗糙结构两个方面,重点论述了类金刚石薄膜表面润湿调控的方法及研究现状。通过等离子体表面处理、元素掺杂或者化学修饰改变DLC薄膜表面化学组成,实现DLC薄膜表面本征润湿改性。通过基体表面织构化或者薄膜表面形貌控制,构建DLC薄膜表面粗糙结构,控制界面润湿状态。二者共同作用可实现DLC薄膜表面润湿性在超亲水和超疏水之间变化。最后,总结并指出当前类金刚石薄膜表面润湿调控存在的一些关键科学问题,同时展望了未来的发展趋势。

Diamond-like carbon films with special surface wettability especially super-hydrophobicity can fulfill the demand of surface modification of smart interface materials serving under extreme conditions(e.g.,in rain or snow weather,humid environment,or human body)in the fields of machine,electronic,optics and medicine,etc.Herein,the advantages of produce technique and performances and preparation methods of diamond-like carbon films were overviewed briefly.The application background of diamond-like carbon films with special surface wettability especially super-hydrophobicity was presented.Meanwhile,the limitations both in science and technique to freely regulate surface wettability of diamond-like carbon films were also proposed.In this context,the inherent surface wettability of diamond-like carbon films and its relations with microstructures(including hybridization state of carbon atoms and short or medium range ordered sp^(2)-C phase cluster structures)were demonstrated.Next,according to the classical Wenzel and Cassie wetting theories,a comprehensive review was presented on the regulation methods mainly from two different aspects,i.e.,surface chemical compositions and surface rough structures,and recent achievements on surface wettability regulation of diamond-like carbon films.On one hand,changing surface chemical compositions or surface free energy by plasma surface treatment,element doping or surface chemical modification could promote inherent surface wettability modification(i.e.,hydrophilicity to hydrophobicity transition)of diamond-like carbon films.On the other hand,constructing specific surface rough structures on the micro/nano scales by substrate surface texturing or film surface morphology design would control the interface wetting state(e.g.,Wenzel state,Cassie state or the transition state)of diamond-like carbon films.These two effects together gave rise to the variation of surface wettability of diamond-like carbon films between super-hydrophilicity and super-hydrophobicity.Finally,some key scientific issues that hinder the surface wettability regulation of diamond-like carbon films were proposed,and the research prospects and directions of this field were also briefly addressed.