A kelp-inspired polyester fabric surface of UV grafted hydrogel for drag reduction

The resorcinol diglycidyl acrylate (RDA) is firmly introduced to the surface of polyester (PET) fibers by a simple dip-rolling and baking method, and a free radical polymerization reaction is initiated on the surface of PET fabrics under ultraviolet light (UV) light to obtain three hydrogel layers with different structure, including polyacrylamide (PAAM), polyacrylic acid (PAAC) and poly-N-isopropylacrylamide (PNIPAAM). It is shown that the pretreatment-UV grafting method can be used to obtain hydrogel layers with porous structure on the surface of PET fabric, and all three hydrogel layers have better frictional properties than kelp. Among them, the friction coefficient of PET-PAAM surface can reach 0.02, which is 17% of the friction coefficient of kelp surface and 83% lower than that of the untreated PET fabric surface, giving the PET fabric surface excellent interfacial drag reduction characteristics. It can be applied to the surface of underwater activity equipment as well as ships to improve moving efficiency and reduce energy consumption.