Facial Fabrication of Biomimetic Water Pinning Microstructures on Polyethylene Surfaces with Robust Superhydrophobic Wetting State

Applying hot-embossing technology,a simple and cost-effective method for the fabrication of microstructured High Density Polyethylene(HDPE)surfaces with a robust superhydrophobic wetting state is proposed.Micro-meshes and micro-grooves in the flexible template are filled by the PE melt in the hot embossing process.Subsequently,a two-stage microstructure on the PE film surface is formed.This PE film exhibits a contact angle of 151.8°±2°and roll-offangle of>90~when a 5μL water droplet is dropped on its surface.Water pinning ability on the surface is figured out and roll-off angles are as a quadratic function of specified water droplet volume.Specifically,a 356μN water pinng force appears on the HDPE film due to the solid-vapor composite interface on its surface.Meanwhile,self-cleaning and immersion tests reveal that the HDPE surface with micro-pillars exhibit robust Cassie impregnating wetting state against external pressure.The proposed method for facial fabrication ofmicrostructured surfaces is an appropriate candidate for the development of droplet manipulation and functional biomimetic polymer surfaces.