Ma Donghai, Liu Zhongmin, Li Yue, Luo Lingxuan
School of Mechanical Engineering, Hangzhou Dianzi University, No. 1158, 2nd Street, Qiantang District, Hangzhou, China.
Sci Rep. 2024 Nov 14;14(1):28011. doi: 10.1038/s41598-024-78681-z.
Wetting behavior of droplets on a substrate with micro-grooves plays a key role in super-hydrophobicity. This paper aims to study the influence of groove width, droplet size, and surface tension on the anisotropic wetting behavior of droplets on micro-grooved PDMS membranes. Three types of PDMS membranes are made by mold replication. Profiles of droplets along the circumferential direction are observed by HD camera, and the 3D model of the droplet is reconstructed. Capillary forces at the three-phase contact line are obtained using the surface tension integration method. Additionally, liquid's wetting depth within the micro-grooves is calculated using an interfacial free energy equilibrium approach. The experiment shows that the micro-grooved PDMS membrane has anisotropic constrain to droplets due to wetting depth change in micro-grooves. Meta-equilibrium states at the three-phase contact line are influenced not only by substrate free energy, but also by wetting depth, interface pressure, and substrate structure.
液滴在带有微槽的基底上的润湿行为在超疏水性中起着关键作用。本文旨在研究槽宽、液滴尺寸和表面张力对微槽聚二甲基硅氧烷（PDMS）膜上液滴各向异性润湿行为的影响。通过模具复制制备了三种类型的PDMS膜。利用高清摄像机观察液滴沿圆周方向的轮廓，并重建液滴的三维模型。采用表面张力积分法获得三相接触线上的毛细力。此外，使用界面自由能平衡方法计算微槽内液体的润湿深度。实验表明，由于微槽内润湿深度的变化，微槽PDMS膜对液滴具有各向异性约束。三相接触线上的亚平衡状态不仅受基底自由能的影响，还受润湿深度、界面压力和基底结构的影响。
