Facile fabrication of superhydrophobic polyimide/polytetrafluoroethylene composite coatings with high water adhesion

A facile casting method was used to fabricate superhydrophobic polyimide/polytetrafluoroethylene composite coatings with high water adhesion. The water contact angles of the composite coatings were larger than 150 °, expressing superhydrophobic property. But water droplets pinned tightly on the composite coating, even if it was upside down. The X-ray photoelectron spectrum analysis indicated that polyimide and polytetrafluoroethylene coexisted in the resulting coating. The observation with scanning electron microscopy showed that the composite coating formed lotus-like structure with many spherical polyimide papillae randomly bonding on the surface. But the tops of the polyimide papillae were not covered by lance-shaped Teflon fibres, forming an inhomogenous and discontinuous surface structure. This special surface chemical distribution and lotus-like structure combined to contribute to the high adhesive superhydrophobicity. This simple method may greatly extend the application range of high adhesive superhydrophobic surfaces in microcontrollable and microfluidic application. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42810.