Sealing method of PDMS as elastic material for MEMS

This paper proposes an effective sealing method of PDMS (polydimethylsiloxane) without losing elasticity of the material. Parylene (poly-para-xylylene) CVD can caulk porous PDMS structure and provide low permeable characteristics. The longstanding drawback is that parylene deposition on PDMS spoils elastic features of PDMS. MEMS devices using deformation of PDMS such as micro pump and micro balloon actuator requires not only high sealing but also high elasticity of PDMS. Deposited parylene permeates PDMS and then forms a film on PDMS. Our key idea is to remove a surface parylene layer on PDMS with the aim of keeping elastic features of PDMS. O₂ plasma etching is applied to remove unnecessary surface parylene. This paper evaluates sealing and elastic features of parylene-caulked PDMS. Componential analysis of provided material by FTIR spectrum (FT-720, HORIBA Inc) is also reported. Parylene-caulked PDMS is applied to pneumatic balloon actuator devices, PDMS membrane-based micro-mirror device, in order to demonstrate advantages of proposed method.