Superhydrophobic Fluorosilane and Alkylsilane Diatomaceous Earth Particles Treated Polyurethane

Hydrophobic and superhydrophobic coatings were prepared using fluorosilane (FS) and alkylsilane (AS) modified diatomaceous earth (DE) with a polyurethane. The thermal properties of modified FS-DE and AS-DE were probed using thermogravimetric analysis yielding 3.8% and 6.8% silane adsorption, respectively. The hydrophilicity and morphology of the materials were analyzed using contact angles and scanning electron microscopy. The water contact angles were studied as a function of the particle loadings of fluorosilane and alkylsilane modified DE in the coatings. The water contact angles reached superhydrophobicity (water contact angles ≥ 150°) with 20% and 30% particle loadings of FS-DE and AS-DE, respectively. For FS-DE, the contact angle reached 160° with more than 20% particle loadings, while AS-DE remained superhydrophobic between 30-50% particle loadings. Above 50% AS-DE particle loadings, the contact angles were reduced. These results were consistent with those from scanning electron microscopy.