Durable and self-healing superhydrophobic polyvinylidene fluoride (PVDF) composite coating with in-situ gas compensation function

A durable and self-healing superhydrophobic polyvinylidene fluoride (PVDF)/polyester-modified silicone resin (PMSR)/microspheric Na 2 CO 3 @SiO 2 coating with WCA of 158   ±   1.5° and low SA of 4   ±   0.5° has been successfully prepared via sol-gel and spraying technique. After 24   h hydrolysis of tetraethylorthosilicate (TEOS), microspheric Na 2 CO 3 @SiO 2 particles with extremely large storage spaces were obtained as reservoirs for the healing agent of POTS. The superhydrophobicity of the prepared coating can be recovered after 10 rubbing/healing test cycles, indicating the excellent self-healing ability. Simultaneously, the prepared coating also possesses gas compensation capability in acidic condition, which can extend superhydrophobic duration by 400%. The gas compensation capability can be mainly attributed to the bubbles generated from the reaction between acid and porous Na 2 CO 3 , hindering water wetting the surface. Moreover, the prepared coating can withstand 4217 friction cycles without obvious surface damage, which is approximately 6 times higher than that of pure PVDF coating. This is mainly due to the combined action of the high adhesion of PMSR, the self-lubrication of PVDF and the surface hierarchical nano/micro wrinkles. The prepared coating also shows prominent superhydrophobic stability under the conditions of acid/alkaline solution (pH   =   1–14) or strong UV exposure (14   days). It is believed that this durable and self-healing superhydrophobic coating is anticipated to open a new avenue to enlarge the application range of superhydrophobic coatings.