A multifunctional graphene composite coating with switchable wettability

Abstract Although many encouraging advances have been made, the further development of the switchable wettability surfaces has been limited by complex preparation process, limited substrate materials, and inconvenient switching wettability methods. Herein, a multifunctional graphene composite coating (MGCC) with switchable wettability was fabricated by simple methods. Attributed to the special properties of nano-TiO2 and graphene, the MGCC can achieve reversible wettability transformation under UV or IR irradiation. The unique wettability and good adhesion make MGCC show potential advantages in many fields. First, spraying MGCC on metal foam or melamine sponge can achieve high-efficiency separation of oil-water layered mixtures (> 97.4%) or emulsions (> 99.1%). Secondly, due to the light-controlled switchable wettability, MGCC platform can obtain different wettability regions by mask method to manipulate droplets or fluids. Different wetting models (Cassie state, Cassie impregnation wetting state, and Wenzel state) could be realized on the same MGCC surface. Thirdly, MGCC can significantly improve the corrosion resistance of metal surface, providing a new solution for corrosion protection. More specifically, the corrosion inhibition efficiency was 99.996%. Finally, MGCC has good anti-icing and active deicing abilities, which are attributed to the superhydrophobicity and excellent photothermal properties of graphene. In particular, ice adhesion strength (IAS) of MGCC surface was only 117 ± 15 kPa, and the ice shear strength (ISS) was only 183 ± 18 kPa. This study provides a new idea for designing a simple, multifunctional, and switchable wettability coating, which is expected to promote the large-scale preparation and application of functional integrated smart surface.