Self-cleaned zirconia coatings prepared using a co-precursor sol–gel method

The experimental work on the self-cleaned zirconia coatings prepared using a co-precursor sol–gel method is presented here. The zirconia coatings were synthesised using zirconium n-propoxide (ZrPro) precursor and different organosilanes such as trimethyl cholorosilane (TMCS), hexamethyl disilzane (HMDZ) and perfluorodecyl triethoxy silane (FDTES) as co-precursors. The organosilanes have a profound impact in modifying the surfaces making them water repellent. Therefore, the influences of various organosilane co-precursors on the chemical structure, thermal stability, hydrophobicity and roughness of the zirconia coatings were studied by varying the ZrPro:Co-precursor molar ratios. FTIR spectra of zirconia coatings revealed the high intensity of peaks related to C–H, Si–C and Zr–O–Si chemical bonds manifesting their hydrophobic characteristics. The TMCS and HMDZ co-precursors-based hydrophobic zirconia coatings retained their hydrophobicity up to a temperature of 300 °C as confirmed from TG-DSC analyses. The maximum contact angle of 154° and roughness of nearly 0.316 μm were measured for zirconia coatings prepared using the ZrPro:TMCS molar ratio of 0.3. These superhydrophobic zirconia coatings can be applied for the self-cleaning purpose.