Self-lubricating SU-8 Nanocomposites for Microelectromechanical Systems Applications

Abstract

SU-8 is an industrially useful photo-resist polymer for microfabrication because of its unique UV-sensitive curing property. It is also used as a structural material for micromachines such as microelectro mechanical systems (MEMS). However, it has poor tribological and mechanical properties which make SU-8 inferior to Si, the mainstay MEMS material today. In this paper, we report the fabrication of SU8 nanocomposites which are selflubricating and have better mechanical properties. The liquid lubricant i.e., perfluoropolyether (PFPE) and nanoparticles such as SiO2, CNTs, and graphite were added into SU-8 for this purpose. These selflubricating SU8 + PFPE and SU-8 + PFPE + nanoparticle composites have shown a reduction in the initial coefficient of friction by ∼6-9 times and increased wear life by more than four orders of magnitude. The mechanical properties such as the elastic modulus and the hardness have increased by ∼1.4 times. These SU-8 nanocomposites can be used as a self-lubricating structural material for MEMS applications requiring no external lubrication. As well, these nanocomposites can find applications in many tribological components of traditional machines. © Springer Science+Business Media New York 2012.