Self-cleaning hydrophobic acrylic coatings were prepared by fluorine-free octadecyl mercaptan(ODT).The self-cleaning,contact angle,water absorption,inhibition efficiency,molecular architecture and dynamic mechanical analysis(DMA)of acrylic coating before and after modification were analyzed.The results showed that the substrate surface with thiol modification had micro rough structure with low surface energy,and the"air cushion effect"made the surface good self-cleaning.The contact angle increases as ODT was added,along with the change from hydrophilicity to hydrophobicity.Adding 5%ODT,the hydrophobicity reached the highest,and also there was an obvious"marginal papillae"structure on the surface,and the contact angle was increased by 38.52°.The water absorption of modified film was reduced,and was only 0.31%when adding 5%ODT,showing the lowest absorption.The addition of ODT could improve the corrosion resistance of acrylic resin.When the addition amount was 5%,the inhibition efficiency was the highest.The compact structure and special orientation ar-rangement of quasi crystalline with mercaptans modification was confirmed by FT-IR testing.Mercaptan had good compatibility with acrylic resin,adding thiol reduced the glass transition temperature of film,also reduced its storage modulus and thermal stability,but expanded its flexibility and the effective damping temperature range.