One-step fabrication of self-cleaning superhydrophobic surfaces: A combined experimental and molecular dynamics study

Abstract

A simple one-step approach was developed to fabricate self-cleaning superhydrophobic surfaces by soaking the copper substrates into a mixed solution containing zinc oxide, stearic acid and polyphenylene sulfide molecules. X-ray photoelectron spectra confirmed that the hybridization between organic polymers and inorganic molecules happened. Further scanning electron microscopy analyses revealed that hierarchical structure was formed. A synergy between modified surface chemistry and surface roughness provided copper substrates with superhydrophobic properties and good self-cleaning performance. The fabricated superhydrophobic surfaces exhibited a water contact angle as high as ∼164.7 ± 1.5° and a sliding angle as low as ∼4.0 ± 0.8°. Molecular dynamics simulations were applied to study the adsorption behavior of stearic acid molecules on the zinc oxide crystal surfaces and the wettability of water molecules on as-prepared surfaces at molecular level. Molecular dynamics simulation results illustrated that the hydrophilic interactions between water droplets and zinc oxide surfaces involved hydrogen-bond formation, whereas the hydrophobic interaction between water molecules and superhydrophobic surfaces involved Van der Waals's interaction between the alkyl chains.