Facile Preparation of AZO ‐Functionalized Cotton Fabrics With High Infrared Reflectance via a Conventional Pad–Dry–Cure Process

Passive personal thermal management textiles with effective infrared (IR) shielding are highly sought after for outdoor cooling purposes. Herein, we report an application‐driven paradigm utilizing aluminum‐doped zinc oxide (AZO) nanoparticles on cotton knitted fabric via a conventional pad–dry–cure process. The AZO dispersions were optimized with anionic dispersant BYK‐190, while polyurethane dispersion (PUD) 1087R3 was chosen as the ideal binder. Optimal conditions were identified as an AZO particle size of 100–500 nm, an AZO concentration of 7.5 wt%, and a PUD 1087R3:AZO mass ratio of 1:1. The resulting AZO‐finished cotton fabric demonstrated a high IR reflectance of about 80%, achieved primarily through free‐carrier plasma reflection of AZO nanoparticles. As a result, the fabric's surface temperature decreased by 11.4°C under an IR lamp and, importantly, by 4.4°C under direct summer sunlight compared to unfinished cotton knitted fabric. Additionally, the fabric retained excellent wearability. This study offers a straightforward, scalable, and effective approach for developing high‐efficiency cooling textiles, with significant potential for applications in summer outdoor wearables and personal thermal management systems.