Deformation-based micro surface texturing using soft backing self-alignment for polymeric material

Abstract

The deformation-based micro-surface texturing technique has been widely accepted as an effective method to add function to the surface of materials with the advantages of low equipment cost, easy machine setup and high-mix low-volume production capabilities. In this study, a low-cost deformation-based micro surface texturing process was developed to form single-sided micro-surface texturing on polystyrene petri dishes with local heating in atmospheric environment using soft backing self-alignment mechanism. A nickel mold, having micro-groove surface patterns with height and width of 2 μm and spacing of 6 μm, was produced by photolithography and electroforming. During the texturing process, the nickel mold was heated to a temperature slightly above the Tg before pressing down to the workpiece, which was rested on a non-heated flat backing. The effect of different holding time, temperature and force on the surface texture profile of the petri dish, which was rested on different backings, was studied. The result shows that PU rubber soft backing is more suitable to achieve high surface replication fidelity than the rigid backing, yet still maintaining good repeatability. With soft backing, the substrate is able to self-align, allowing homogeneous contact between the mold and the substrate to achieve excellent feature replication without usage of expensive precision alignment tools. Preliminary biological test on the textured petri dishes show that the formed micro surface texture is able to introduce directional growth in the cell culturing process.