Hydrophobic Coating Based on Fluorinated Acrylate Monomer Using UV-LED Polymerization

Water repellent or hydrophobic coating offers various promising advantages such as anti-fouling and anti-corrosion surface properties. It is well known that fluorine based moiety can alter the surface wettability due to its low surface energy characteristic. In this study, UV-curable hydrophobic coating mixture was prepared based on aliphatic urethane acrylate oligomer, 2-ethylhexyl acrylate (2-EHA), methyl methacrylate (MMA), trimethylopropane triacrylate (TMPTA), heptadecafluorodecyl methacrylate (HDFMA) and hydroxyphenyl ketone photoinitiator (Chivacure 300). The reaction mixture was coated onto a glass substrate and cured via UV-LED irradiation. From the ATR-FTIR spectra, the C=C absorption peak at 1635 cm^-1 was decreased after UV-LED irradiation, indicating the proceeding of polymerization. The effect of HDFMA content on the properties of UV-curable coating was investigated. In order to quantify the degree of hydrophobicity, water contact angle of the coating was determined. The addition of fluorinated acrylate monomer improved the water repellence behaviour and increased the water contact angle from 86.01° to 123.57°. As the HDFMA content increased, the surface tension of the coating also became lower, due to the presence of the fluorinated group. Moreover, the light transmittance of the coating layer was not significantly affected with increasing HDFMA content. It can be concluded that the fluorinated containing monomer gave the most contribution towards the hydrophobicity of the coating assisted by UV-LED curable system. Analogously, these results may attain various potential applications such as self-cleaning, optoelectronic and liquid-repellent coating. Importantly, the utilization of UV-LED in this research was a great initiative to develop green aspect for photopolymerization.