有机基材表面亲水-疏油润湿性能的分子尺度调控研究

Heterogeneous surfaces that have both hydrophilic and oleophobic moieties exhibit special oleophobic yet hydrophilic wetting behavior, based on the rearrangement of the two moieties. Such surfaces are very promising for applications such as self-cleaning, anti-fogging, oil-water separation, and oily waste water treatment membranes. However, most of the reported hydrophilic-oleophobic coatings have relatively long water wetting time, which makes the anti-fogging effect not simultaneously and also affects the oil-water separation performance. At present, it is still challenging to control the water wetting behavior on such surfaces in molecular scale. This project aims to tailor the availability of valid space for the oleophobic chains to reconstruct and water molecules to penetrate, and thus the water wetting behavior, through the concept of utilizing short-chain “spacer” to control the inter-chain distance of oleophobic moieties. Photo-reactive hydrophilic-oleophobic block oligomers will be synthesized and photo-grafted onto organic substrates together with photo-reactive short-chain spacers. The photo-grafting method to be used in this project is substrate-independent for organic substrates, which will overcome the shortage of lacking covalent bonding between coatings and substrates, as well as the need of specific reactive groups on substrates, facing the current fabrication methods. The correlation between the elemental composition of the heterogeneous surfaces and the wetting properties will be systematically studied, and the highest inter-chain distance to achieve the lowest water wetting time but still ensure good oleophobicity will be clarified. For application studies, various fabrics and filtration membranes will be used as substrates to evaluate the self-cleaning and anti-oil contamination performance, as well as the durability of the coatings.

含有亲水和疏油组分的异质表面展现出特殊的亲水-疏油润湿性能，其在自清洁、防雾、油水分离、抗油污型油类污水处理膜等领域应用前景良好。然而，现有研究体系的水滴润湿时间较长，不能达到即时防雾效果或会影响油水分离性能，而现今如何从分子尺度对其润湿性能进行调控仍存在挑战。本项目拟通过引入短链间隔单元的策略，控制相邻疏油链段的间距，以调控疏油链段重新架构的自由度和水分子渗透的难易程度，从而达到调控润湿性能的目的。将合成光反应性亲水-疏油嵌段低聚物，发展普适于有机基材的光化学接枝法共价键构筑的新方法，以突破现有体系的涂层与基材间缺乏有效键接、方法普适性差的局限，为此类表面的广泛应用提供研究基础。将研究异质组分结构与润湿性能的构效关系，确立能达到最短水滴润湿时间的边界条件，并以织物材料和过滤分离膜为例评估其实用性，达到优良的耐久性自清洁与抗油污性能的目标。

本项目针对原有亲水-疏油表面研究体系中水滴润湿时间较长的问题，从分子尺度对亲水-疏油异质表面结构进行有效调控，实现了高疏油性与水滴毫秒级瞬时润湿的统一。本项目首先采用表面光化学接枝法对棉和涤纶织物材料以及有机过滤膜进行亲水疏油改性，并通过引入共聚单体作为短链间隔单元，达到了调控疏油性及水滴润湿时间的目的。然后，采用光化学聚合交联法在涤纶织物表面构建亲水-疏油的异质表面，详细研究了异质组分结构与亲水-疏油润湿性能之间的构效关系，确定了实现短至68毫秒的水滴润湿时间的组分比例条件，并评估了所得亲水-疏油涤纶织物的自清洁、易去油污性能及附加的吸湿与抗静电性能。另外，针对亲水-疏油多孔材料在有效吸附去除油中微量水分中的独特优势，基于异质组分结构的调控，制备得到了多种亲水-疏油多孔材料。本项目重点探究了表面光化学接枝法、光化学聚合交联法、乳液界面聚合法等技术手段以及引入共聚单体作为短链间隔单元、无规共聚/共混等策略，在实现不同材料的亲水-疏油改性中的应用，并通过改变间隔单元的用量或亲水-疏油单体的比例等方式实现了对疏油性及水滴润湿时间的调控。研究结果表明，所得亲水-疏油材料在自清洁、抗油污、油中微量水的去除等方面具有良好的应用前景。