水泥基超疏水材料自清洁技术研究进展

Research Progress of Self-cleaning Technology of Cement-based Superhydrophobic Materials

超疏水材料是一种新型智能仿生材料,具有优良的自清洁、抗凝冰、防腐等性能,已广泛应用于航天、建筑、电力等领域。但在公路交通领域尚处于探索研究阶段。水泥基超疏水材料自清洁技术源于自然界的“荷叶效应”,超疏水表面的微纳结构和低表面能降低了污染物与涂层的粘附力,赋予超疏水表面优异的自清洁性,为水泥基材料的主动防污技术提供了新思路。目前,水泥基超疏材料自清洁理论与技术尚不成熟,主要通过表面微纳米复合结构和低表面能化学物质协同制备水泥基超疏水材料,从而实现水泥基材料自清洁功能。水泥基超疏水材料的制备技术主要包括表面疏水改性和本体疏水改性两种。硅烷/硅氧烷类和硬脂酸等疏水材料因其环保、成本相对低廉,使用频率较高。水泥基表面超疏水涂层处理类型主要包括涂覆法、模板法、层层自组装法等。表面超疏水改性对水泥基材料力学强度的影响较小,而整体超疏水改性因内掺疏水材料,延缓水泥水化反应,降低了水泥基材料的力学强度。水泥基表面超疏水涂层因其施工简便、性价比高、能耗低,应用更为广泛。水泥基超疏水材料自清洁性能评价方法尚未统一,其中以模拟污染物收集法应用较为广泛。由于水泥基材料工程结构复杂,影响因素众多,从实际工程应用来看,水泥基超疏水材料的制备技术、评价方法、耐久性仍需进一步研究。本文归纳了水泥基超疏水材料自清洁技术的研究进展,分别对超疏水表面自清洁机理、水泥基超疏水材料制备技术、水泥基超疏水材料性能、水泥基超疏水材料自清洁性能评价方法等方面进行了综述,分析了水泥基超疏水材料自清洁技术面临的问题并展望了其前景,以期为制备环保、耐久的新型水泥基超疏水材料提供参考。

Superhydrophobic materials,as a new family of intelligent bionic materials,have been widely used in aerospace,construction,electricity gene-ration and other fields,due to their excellent self-cleaning,anti-ice-condensation and anti-corrosion properties;however,their use in the highway transportation field is still in the exploratory stage of research.The self-cleaning properties of cement-based superhydrophobic materials originate from the‘lotus effect’found in nature.The micro-nano structure and low surface energy of a superhydrophobic surface reduce adhesion between pollutants and the coating.These two effects endow the surface of a cement-based material with excellent self-cleaning properties,thereby providing a new paradigm for the active antifouling of such materials.The theory surrounding the self-cleaning behavior of cement-based superhydrophobic materials is presently immature,as is the corresponding technology.Cement-based superhydrophobic materials are mainly prepared through the cooperation of surface micro-nano composite structures and low surface energy chemicals,which facilitate their self-cleaning functions.Techniques for preparing cement-based superhydrophobic materials mainly include hydrophobically modifying surfaces and integrating hydrophobic modifications.Hydrophobic materials like silanes/siloxanes and stearic acid are frequently used,because they are environmentally friendly and inexpensive.Treatment methods that endow the surfaces of cement-based materials with superhydrophobicity mainly include coating,templating,and layer-by-layer self-assembly.Superhydrophobically modifying a surface has little effect on the mechanical strength of the cement-based material,while integral superhydrophobic modification delays cement hydration reactions and reduces the mechanical strength of the cement-based material through the inclusion of the hydrophobic material.Cement-based superhydrophobic surface coatings are more widely used,because of simple construction,cost effectiveness,and low energy consumption.While methods for evaluating the self-cleaning performance of cement-based superhydrophobic materials have not been unified,the simulated pollutant collection method is widely used.Preparation techniques,evaluation methods and material durability require further study from the perspective of practical engineering applications,as multiple factors affect the engineering structures of cement-based superhydrophobic materials.In this paper,we summarize progress in self-cleaning-technology research for cement-based superhydrophobic materials.The self-cleaning mechanisms of superhydrophobic surfaces,preparation technologies,performance analyses and methods for evaluating the self-cleaning performance of these materials are introduced.Problems associated with this self-cleaning technology are discussed,and prospects are proposed,with the aim of providing a reference for the preparation of durable and environmentally friendly new cement-based superhydrophobic materials.