Anti-scaling of superhydrophobic poly(vinylidene fluoride) composite coating: Tackling effect of carbon nanotubes

Superhydrophobic poly(vinylidene fluoride)/fluorinated ethylene propylene/SiO2 (PFS) composite coatings incorporating various carbon nanofillers, such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene nanoplates (GnPs) and carbon black (CB) respectively, were successfully fabricated by spraying. The scale-inhibition properties of these coatings were tested in a CaCO3 supersaturated solution, and the deposited CaCO3 scale was characterized with SEM and XRD. The effects of carbon nanofillers on the surface roughness, surface energy, and scale inhibition behaviors of different coatings were studied. In contrast with GnPs, CNFs and CB, the CNTs were dispersed more uniformly in the PVDF matrix and formed a stronger bond with the polymer matrix. The addition of CNTs changed the morphology, increased the surface roughness, and further reduced the surface energy of the superhydrophobic PFS-CNTs composite coating owing to the tackling effect of CNTs. A stable air film was maintained on the surface of superhydrophobic PFS-CNTs composite coating, which was more favorable for superhydrophobic retention by wrapping air in the saturated CaCO3 solution. The CaCO3 scaling rate on the superhydrophobic PFS-CNTs composite coating was only 44 % of that on the hydrophobic PFS composite coating, which showing the highest antiscaling performance.