A comprehensive study on the self-lubrication mechanisms of SU-8 composites

Poor tribological properties of SU-8, a promising MEMS structural material, have been recently addressed by developing a perflouropolyether (Z-dol) lubricant droplet-filled SU-8 composite. The composite shows wear durability four orders of magnitude greater than that of SU-8. The chemical reaction between the SU-8 and PFPE molecules and the physical self-lubrication mechanism were found responsible for this dramatic improvement. In this work, the self-lubrication mechanism at the ball-composite interface of SU-8+5 wt% Z-dol composite was further investigated by varying sliding speed. Effects of normal load on the tribological responses of SU-8+5 wt% Z-dol composite was also investigated independently and various possible wear mechanisms are proposed.