Tuneable Wetting of Fluorine‐Free Superhydrophobic Films via Titania Modification to Enhance Durability and Photocatalytic Activity

Abstract

Superhydrophobic photocatalytic self‐cleaning films are fabricated via aerosol‐assisted chemical vapor deposition (AACVD). First, superhydrophobic/SiO2 polymer films consisting of a combination of fatty acids, polydimethylsiloxane (PDMS) and SiO2 nanoparticles are deposited which displayed static water contact angles >160° and maintained superhydrophobicity after 300 tape peel cycles. The AACVD process is used to achieve a highly textured morphology required for superhydrophobicity. The surface properties are then modified by depositing a thin layer of TiO2 on the superhydrophobic coating via AACVD of titanium isopropoxide (TTIP). The deposited films are hydrophobic/superhydrophobic depending on the concentration of TTIP used in the deposition process. The resulting hybrid films exhibit enhanced photocatalytic activity relative to the uncoated superhydrophobic film, maintained hydrophobicity after exposure to toluene, and tolerated pencil hardness of up to “6H”. This multi‐layered approach allows to easily tune the wettability of the superhydrophobic film, which is challenging to do when the superhydrophobic and TiO2 precursor are deposited as a single one‐pot precursor.