Fluorine and Siloxane Free Waterborne Near Superhydrophobic Organic Coating Based on Styrene Acrylic Polymer Emulsion through Surface Engineering

A superhydrophobic coating, free of fluorinated and siloxane materials, has been prepared via reactive compatibilization of all organic blends of hydrophilic and hydrophobic materials. In this case, styrene acrylic emulsion and a combination of hydrophobic waxes (functional rice bran wax and functional polypropylene wax) are blended together in the presence of polycarbodiimide as the reactive compatibilizer. The effect of blending and crosslinking on surface morphology is studied by Fourier transform infrared spectroscopy analysis, microscopy analyses (SEM and AFM), contact angle, and surface energy measurements. After heat treatment and crosslinking, synergistic improvements of surface properties with a gradual trend toward superhydrophobicity are observed (water contact angle approximate to 144 degrees and roll-off angle of <10 degrees). The system is free of nanoparticles, and the desired surface morphology and microstructure is formed from the mixture of renewable (rice bran) wax and petrochemical (polypropylene) wax. These coatings are shown to have easy-cleaning as well as self-cleaning characteristics. Further, the coatings can withstand exposure to solvents as well as mechanical abrasion.