Fabrication of PDMS micro through-holes for electrochemical micromachining

Abstract

Surface texture has played a fundamental role in the development of many advanced fields. Through mask electrochemical micromachining (TMEMM) is a feasible alternative for fabricating surface textures. In this paper, polydimethylsiloxane (PDMS) is firstly employed as a mask in TMEMM due to its chemical resistance, low cost, flexibility and high moulding capability. A simple method for fabricating PDMS micro through-holes is proposed. A vacuum-aided process was introduced to fill a PDMS gel into an SU-8 mould, and the PDMS gel was solidified in an oven. Then, the cured PDMS micro through-holes were peeled off of the SU-8 mould. PDMS micro holes with a minimum diameter of 50 μm and a thickness of 200 μm were obtained. Furthermore, the PDMS micro through-holes were then used as a mask to prepare a micro dimple array by TMEMM. Experiments were conducted to verify the feasibility of the proposed approach, and the effect of applied voltage and machining time on the diameter and depth of the micro dimple was investigated. Finally, an array of micro dimples 109 μm in diameter and 9.7 μm deep was successfully fabricated by using PDMS.