Electrophoretically deposited carbon micro and nanospheres thin films as superhydrophobic coatings

In this work, we have introduced an electrophoretic deposition method to obtain superhydrophobic carbon micro and nanospheres thin films on fluorine tin oxide coated glass as a substrate. Carbon spheres with different diameters (ranging from 50 to 4500nm) were prepared using a hydrothermal method with DI water and glucose as precursors at 160°C in various hydrothermal processing times (4, 12 and 18h) and glucose concentrations (0.75 and 1M). X-ray diffraction patterns, energy dispersive spectroscopy, Fourier transform infrared spectroscopy and Raman spectroscopy proved graphitic structure of carbon micro and nanostructures, and scanning electron microscopy images showed that the carbon particles were synthesized properly in a sphere shape. Effect of heat treatment and removing of functional groups on the wetting properties has been investigated. By use of a generalized model of wettability we have obtained the relationship between the surface roughness, surface tension and water contact angle. The water contact angles of 162.5 and 157.6° were obtained for the thin film of nanospheres with diameters of about 185nm (0.75M and 18h) in the experimental measurements and theoretical calculations, respectively that shows the system completely obeys the Cassie-Baxter model. [Display omitted] •An electrophoretic deposition method was used to obtain superhydrophobic carbon spheres thin films for the first time.•A change in wettability from hydrophilicity to superhydrophobicity was observed before and after heat treatment.•A model to describe wettability of the spherical particles thin films proposed.