Fabrication of Robust Superhydrophobic Polyester Fabrics with Photothermal Conversion and Oil–Water Separation Performance through Deposition of Natural Polyphenols

Superhydrophobic polyester (PET) fabrics were created by increasing fabric surface roughness and decreasing surface energy through interactions between natural polyphenols, ferrous sulfate heptahydrate, and hexadecyltrimethoxysilane. The superhydrophobic fabric can be obtained with different natural polyphenols, including tannic acid, ferulic acid, gallic acid, guaiacol, and caffeic acid. Durability tests were carried out on the superhydrophobic PET fabric, investigating resistance to washing, rubbing, UV aging, acids, alkalis, and organic reagents. The results demonstrate the stability and versatility of modified PET in complex environments. The modified superhydrophobic PET fabric exhibited exceptional oil-water separation and self-cleaning properties, exhibiting a water contact angle of 161.3° and a sliding angle of 4°. In addition, the modified fabric demonstrated a remarkable photothermal conversion efficiency, with the surface temperature increasing from 29.1 to 72 °C in 300 s, and it maintained a degree of photothermal conversion capability even upon completion of four cycles. This study offers novel perspectives on extending the utilization of natural polyphenols for constructing durable, robust, and multifunctional superhydrophobic fabrics.