PDMS-PI composite coating toward multi-purpose development: Hydrophobic, low-friction/wear, and heat-resistance

Despite polyimide (PI) has been regarded as heat-resistant aviation material, but its high friction coefficient and insufficient abrasion resistance hinder the wide application. Herein, a versatile PDMS-PI composite coating with double-layer structure was prepared by crosslinking hybrid. The effect of polydimethylsiloxane (PDMS) on the hydrophobic, heat-resistant and tribological properties of PDMS-PI composite coating was explored. As expected, compared with the PI and SiO2-PI, PDMS-PI coating achieved the contact angle of 108.5° and only 5 wt% heat loss temperature at 578 ℃. Additionally, its wear rate obviously decreased by 38.5 %, and the friction coefficient declined from 0.33 to 0.07. The improvement contributes to excellent hydrophobic and heat resistance of dense protective layer and low-friction/wear of the PDMS coating layer.