水下可恢复超疏水表面的设计、制备及机理研究

Underwater superhydrophobic materials have great potential applications in underwater gas collection, drag reduction of vehicles, anti-corrosion etc. However, underwater superhydrophobic surfaces usually turn into Wenzel state from Cassie state due to the hydrostatic pressure, gas dissolution and other factors, which leads to the loss of superhydrophobicity. In this research, we put forward a novel idea for underwater restoring superhydrophobic coating based on the aerophilicity of sparse rough surface and bubble introduced dewetting mechanism. Firstly, the underwater formation and expansion of interface will be studied, and the relationship between the bubble wettability and microstructure will be established. In the following, stringed nanoparticles coating will be controllably fabricated by electric adsorption and chemical vapor deposition methods. Sparse microstructures with high roughness would be obtained due to the anisotropy and self-assembly of heteromorphic particles. Furthermore, the hydrophobicity in air/underwater will be tested and the bubble introduced dewetting process will be real-time observed, thus the restoring mechanism of underwater superhydrophobicity will be discussed. This project aims to provide a facile, novel route for the long-term underwater superhydrophobic materials.

水下超疏水材料在水下气体收集、水下航行器减阻、船体防腐蚀、等领域均具有巨大的应用前景，但由于水压、气体溶解等因素导致水下超疏水材料表面易从Cassie状态转变为Wenzel状态，从而失去超疏水特性。对此，本项目拟利用稀疏微结构易于粘附气泡、具有亲空气性的特点，通过气泡诱导恢复水下超疏水性。本项目通过研究水下固-气-液三相界面的形成及扩展过程，建立气泡润湿性与微结构的关联；结合电荷吸附法和化学气相沉积法可控制备链状纳米粒子涂层，发挥异形粒子的各向异性及自组装特点，获得高粗糙度、稀疏的表面微结构；通过表征空气/水下疏水性、实时观测水下气泡诱导去润湿过程，探究气泡诱导下超疏水表面的可恢复性机理。本项目旨在为长效、稳定的水下超疏水材料提供一种简易可行的新途径。

水下超疏水材料在水下气体收集、水下航行器减阻、船体防腐蚀等领域均具有巨大的应用前景，但由于水压、气体溶解等因素导致水下超疏水材料表面易从Cassie状态转变为Wenzel状态，从而失去超疏水特性。对此，本项目拟利用稀疏微结构易于粘附气泡、具有亲空气性的特点，通过气泡诱导恢复水下超疏水性。本项目制备得到了三维旋转结构的具有高度各向异性的链状纳米粒子，链长最长可达144nm。通过电荷吸附和低表面能硅烷化处理制备得到高粗糙度、稀疏的超疏水涂层，粗糙度可达36nm，涂层表面水接触角可达170°，透光率可达90%以上。超疏水涂层预润湿后，气泡在表面可实现附着和扩展，气泡在涂层表面的接触角可由刚接触时的125°减少至75°，气泡与完全润湿的涂层之间的排斥力仅为0.4nN，具有水下亲空气的性能，通过气泡诱导的方法，在涂层表面连续注入气泡后，可实现涂层表面从Wenzel状态转变为Cassie状态。研究发现涂层结构单元的形状和结构参数（间距、高宽比等）对超疏水表面水下可恢复性能至关重要。制备得到的涂层可简化为截锥形结构，涂层的气体分数（φ）的范围为0.93-0.96，高宽比（H / L）的范围为0.1-0.18，满足气泡附着和自发扩展所需要的结构形状和结构参数条件，可通过气泡诱导实现水下可恢复。制备得到的超疏水涂层由于具有水下亲空气性能，因此可应用于水下呼吸、水下气体收集和水下自修复的领域。同时本项目中链状纳米粒子制备得到超疏涂料，在混凝土和木材的易除冰和抗冻融上显示出优异的性能。