木材表面有机/无机杂化超疏水膜的可控制备及其稳定性研究

Superhydrophobic treatment of wood surface is a novel way of wood modification to impart wood with attractive properties such as water-repellency, anti-mould/decay, and self-cleaning functions. However, the mechanical stability and durability of the fabricated superhydrophobic film on wood substrate remain an unsolved puzzle, which limits the practical application of superhydrophobic wood. In this project, inspired by the lotus effect, robust and durable organic-inorganic hybrid superhydrophobic films are fabricated on the intrinsically heterogeneous wood substrates via a simple dip-coating method by using environment-friendly and chemically stable inorganic silica (SiO2) nanoparticles as inorganic fillers and transparent, adhesive polymers such as polydimethylsiloxane (PDMS) and epoxy resin as organic matrices. Robust superhydrophobic properties are achieved through proper design of the hybrid coatings microstructure. The effects of polymer types, concentrations, polymer/SiO2 mass ratios and film-forming parameters etc. on the morphology and microstructure of the coatings, surface roughness and water-repellent properties (water contact angle and sliding angle) will be systematically investigated, with particular emphasis on the influences of polymer concentrations and polymer/SiO2 mass ratio on the mechanical stability and durability of the superhydrophobic film. Multiple structural and chemical characterizations such as FE-SEM、AFM、FTIR、XPS will be applied in combination to examine the morphology of the nanoparticles and their aggregates in the coatings, surface roughness, elemental compositions, functional groups, chemical bonding modes in order to clarify the formation and tuning mechanism of superhydrophobic film on wood surfaces, which is of significance for the practical application of superhydrophobic wood.

木材表面超疏水改性是获得集防水、防霉防腐、自清洁性能为一体的木材功能性改良新途径，然而超疏水膜的机械稳定性和耐久性一直是限制超疏水木材实际应用的“瓶颈”问题。本项目基于“荷叶效应”仿生学原理，以环境友好、性质稳定的纳米SiO2为无机填料，以具有粘结作用的透明聚合物（PDMS、环氧树脂）为有机基质，采用工艺简单的浸渍涂膜法在木材表面构建高强耐久的有机-无机杂化超疏水膜，通过合理的膜层微观结构设计，赋予木材稳定的超疏水性能。研究聚合物类型、浓度、聚合物/SiO2配比、成膜参数等工艺参量对膜层微观结构形貌、表面粗糙度以及疏水性能的影响及调控规律；重点考察聚合物浓度及其与SiO2配比对超疏水膜机械稳定性和耐久性的影响；应用FE-SEM、AFM、FTIR、XPS等表征手段分析膜层纳米颗粒形貌、聚集状态、表面粗糙度、元素组成、官能团类型等，阐明超疏水膜的形成及其界面调控机制，促进超疏水木材的实际应用。

项目针对木材表面超疏水膜机械稳定性和耐久性差这一限制超疏水木材应用的瓶颈问题，基于“荷叶效应”仿生学原理，以无机纳米材料（如SiO2、TiO2）为填充物，以透明聚合物（如环氧树脂、PDMS）为成膜剂和粘合剂，在木材表面构建了具有可控微/纳米结构的有机-无机杂化超疏水膜，利用粘合剂增强纳米颗粒与木材基底的结合，以改善超疏水膜的机械稳定性和耐久性；阐明了高强耐久超疏水膜的形成与调控机制，提出了木材表面机械耐磨、自修复型超疏水膜构建新方法，为超疏水木材的实际应用提供理论与技术参考。此外，以天然轻木为原料，通过木材细胞壁结构调控和疏水功能化处理创制了一种可重复利用的高弹木材海绵吸油材料，拓展了超疏水木材在油水分离领域的应用。相关研究结果发表在《ACS Nano》、《Materials & Design》、《Applied Surface Science》、《Holzforschung》、《南京林业大学学报》等国内外重要学术刊物；授权国家发明专利2件。