SU8 etch mask for patterning PDMS and its application to flexible fluidic microactuators

摘要

A method to etch structures in silicone rubber could prove useful for microfluidics, lithography and even soft robotics applications. Michael De Volder at the University of Cambridge, United Kingdom, and his colleagues at the KU Leuven, Belgium used a dual-layer mask consisting of a lift-off resist underneath an SU-8 photoresist layer to protect selected areas of the silicone polydimethylsiloxane (PDMS). Next, the team used reactive-ion etching with a specific gas composition to remove the exposed PDMS. The entire protective mask was then easily removed by etching the lift-off layer through exposure to a developer fluid. The researchers used their method to make simple, flexible fluidic actuators. The fabrication process removes the need for imprecise manual cutting or metal masks that introduce defects into PDMS structures, which should enable even greater scaling down of PDMS devices.