Thermoresponsive N,N‐Diethylacrylamide Grafted <scp>SRT</scp> Polyester Fabric for Dynamic Humidity Regulation in Functional Textile

ABSTRACT Efficient sweat evaporation during exercise or prolonged exertion is essential to maintain thermal comfort. Herein, we report a thermoresponsive polyester textile engineered by grafting N,N‐diethylacrylamide (DEAA) onto a commercial PET/PEG copolyester (SRT) to produce poly(SRT‐g‐DEAA). The graft copolymer was melt‐blended into masterbatch pellets, melt‐spun into 75 D/72 F draw‐textured yarns, and fabricated into single‐jersey fabrics. Structural, thermal, and optical characterization confirmed successful grafting and revealed a lower critical solution temperature (LCST) of approximately 31°C–32°C, corresponding to a reversible transition from hydrophilic to hydrophobic behavior. Fabrics prepared from the optimized composition (p[SRT‐g‐DEAA]‐1.5) exhibited substantially improved moisture management: drying time was reduced by 45.4% relative to commercial PET, and dynamic water‐evaporation behavior was markedly enhanced. Unlike conventional approaches that rely on post‐finish coatings, this methodology integrates the responsive moiety directly into the fiber matrix, preserving processability and thermal stability in masterbatch form. The resulting textiles demonstrate strong potential for smart sportswear and other functional apparel requiring adaptive temperature and humidity regulation.