流体在固体表面超铺展特性的研究进展

Review of super-spreading of fluids on solid substrates

对流体在固体表面超铺展特性的研究进展进行了综述,总结了具有超铺展特性的动态湿润体系、超铺展特性的影响因素、内在机理以及实验关联式建立和数值模拟方法。部分丙硅氧烷类和烷基乙氧基化物类以及少数离子型表面活性剂溶液具有超铺展特性,浓度和固体表面能是超铺展的重要影响因素。气液界面的浓度Marangoni效应被认为是超铺展过程的控制因素,表面活性剂在气液、固液和三相接触线前缘固气界面的输运和吸附对浓度Marangoni效应有重要影响。分析认为,实验方面未来应拓展实验体系,建立超铺展产生的判据;深入研究宏观影响因素以及微观输运和吸附机理,同时考虑外加物理场影响,为超铺展的实际应用奠定基础。理论方面需综合考虑表面活性剂向界面的输运、吸附对界面性质的作用规律以及浓度Marangoni效应的影响,借鉴相对成熟的牛顿流体动态湿润理论,建立描述超铺展特性的全过程理论模型。数值模拟方面应以分子动力学模拟为基础建立表面活性剂输运和界面吸附的微观物理模型,将其引入流体动力学模型,实现对超铺展过程精确定量化的描述。本文还给出了可能的超铺展体系铺展全过程的物理图景。

The research progress of super-spreading of fluids on solid substrate is reviewed. The super-spreading systems are summarized, and the influence factors, inner mechanism,experimental correlation model and numerical simulation method are also presented. Several trisiloxane or ethoxylated surfactants and a few ionic surfactant solutions have super-spreading phenomenon on corresponding solid substrates, and surfactant concentration and solid surface energy have crucial influence on super-spreading. The Marangoni effect arising from the concentration difference along the vapor liquid interface is recognized as the key mechanism controlling super-spreading. And the surfactant transportation and adsorption on vapor-liquid, solid-liquid and solid-vapor＆amp;nbsp;interfaces have great influence on the Marangoni effect. The research fields for the future are also analyzed. With respect to experimental investigation, the experimental systems should be extended and the criteria for super-spreading should be established. The macroscopic influence factors should be taken into full account. With respect to theoretical investigation, the Marangoni effect as well as the interfacial properties alteration based on surfactant transportation and adsorption need to be fully considered, a full scale theoretical model could be established based on the theoretical achievement in Newtonian fluid. With respect to numerical simulation, accurate transportation and adsorption model should be established from molecular dynamics simulation and then introduced into the hydrodynamic model to make a precise super-spreading simulation. A possible schematic diagram of the whole spreading process on hydrophobic substrate of super-spreaders is also proposed.