Contact Angle of Water Droplet on Deforming Rubber Sheet with Micro Surface Structures

Interfacial free energy of materials and micro structures on solid surface influence wetting behavior at solid-liquid interface. Controls of wettability by making micro structures on silicon surface have been approached. By reference to those approaches, the authors consider that deformation of micro surface structures changes wettability. In this report, we have made micro surface structures from silicone rubber, and have aimed to change wettability of a droplet by deforming micro structures. We prepared micropillar array on silicone rubber sheet. The diameter and the height of pillar were 200 mu m. The pitch of pillars extended as the rubber sheet extended, and contact angle of water droplet changed. The edge of water droplet jumped from exterior pillars to interior pillars a few times.