Improved super-hydrophobicity of eco-friendly coating from palm oil fuel ash (POFA) waste

Considerable efforts have been made for the fabrication of super-hydrophobic coating for self-cleaning applications. However, a facile, eco-friendly and cost effective coating technology is still a challenging issue. In this present work, a super-hydrophobic glass surface was fabricated using palm oil fuel ash (POFA) waste as silica source and non-fluoro polydimethylsiloxane (PDMS) as surface functionalizing agent. A simple spraying technology was used to coat the super-hydrophobic solution on the glass substrate. POFA was analyzed using XRF, XRD and FT-IR spectroscopy techniques. The super-hydrophobic glass substrates were characterized via FT-IR, FE-SEM, AFM, UV–vis and water contact angle (WCA) analysis. The weight ratio of PDMS to silica solution (SS) (1:0, 1:1, 1:2, 1:3, 1:4, 1:5) on the super-hydrophobicity was studied in detail. A water contact angle (WCA) of 156 ± 1° was achieved when coating the glass substrate with PDMS: SS (1:2). The stability of the coating was evaluated via pH test and UV irradiation experiment, respectively. The results revealed that PDMS:SS (1:2) coated glass substrate is stable and durable in acid-base environment. Upon UV aging, WCA of PDMS:SS (1:2) was greatly improved to 171 ± 2°.