Modelling of spreading, imbibition and evaporation of liquids on structured or porous deformable substrates

液体在具有粗糙度、形貌或多孔涂层的可变形表面上的扩散、吸入和蒸发对于许多工业应用是重要的。这些现象是多尺度的，不能用宏观的方法来描述，它忽略了分子间相互作用的影响。该项目旨在开发液体在结构化或多孔可变形基底上的扩散、吸收和蒸发模型，并考虑到采用分离压力概念描述的表面力的影响。在第一个资助期间，静态和动态润湿液滴的高度与表面力作用的范围进行了研究，使用薄膜理论为基础的数值模型。已经发现，如果纳米滴在可变形固体上扩散，则润湿脊可以表现出非单调动力学。脊形状的演变取决于分离压力等温线的参数。本文研究了拐角几何形状中的毛细驱动流动。在楔形明渠中，表面力决定了细流的最大长度。值得注意的是，当忽略表面力时，稳定的溪流不能被预测。在下一个资助期间，开发的模型将被扩展并用于描述纳米孔中的液体扩散，吸胀和蒸发，在具有地形和机械性能不均匀分布的可变形表面上，以及包含薄柔性片材，薄片和纤维的系统中。这些研究的结果将允许阐明整个多孔结构的尺度上的渗吸的关键现象。在此基础上，将应用均匀化技术计算有效输运系数。这些系数将用于结构化或多孔可变形基底上的吸胀和蒸发的宏观尺度模拟，这与自然现象和技术应用有关。模拟结果将通过与实验数据的比较进行验证。

Spreading, imbibition and evaporation of liquids on deformable surfaces with roughness, topography or with porous coatings is important for numerous industrial applications. These phenomena are multiscale and cannot be described using the macroscopic approach, which ignores the effect of intermolecular interactions. The project is aimed at development of models for spreading, imbibition and evaporation of liquids on structured or porous deformable substrates and takes into account the effects of the surface forces, described employing the disjoining pressure concept. In the first funding period, the static and dynamic wetting of the droplets with height comparable with the range of surface force action has been studied using a thin film theory-based numerical model. It has been found that if the nanodrop spreads over a deformable solid, the wetting ridge can exhibit a non-monotonic dynamics. The evolution of the ridge shape depends on the parameters of the disjoining pressure isotherm. The capillary-driven flow in corner geometries has been studied. The surface forces have been shown to define the maximal length of rivulets in open wedge channels. Remarkably, the steady rivulets cannot be predicted when the surface forces are ignored. In the next funding period the developed models will be extended and used to describe the liquid spreading, imibibition and evaporation in nanopores, on deformable surfaces with topography and inhomogeneous distribution of mechanical properties, as well as in systems containing thin flexible sheets, lamellas and fibers. The results of these studies will allow elucidating the key phenomena governing imbibition on a scale of the whole porous structure. Homogenization techniques for computation of effective transport coefficients will be applied on the basis of this knowledge. These coefficients will be used for macroscopic-scale simulation of imbibition and evaporation on structured or porous deformable substrates, which are relevant to natural phenomena and technological applications. The results of simulations will be validated by comparison with experimental data.