Solvent‐Engineered Polyurethane/Silica Aerogel Coatings for Durable and Thermally Insulating Cotton Fabrics

ABSTRACT This study presents the development of thermoplastic polyurethane (TPU) and silica aerogel powder (SAP)‐based composite coatings for enhancing the thermal insulation performance of cotton fabrics. A solvent pre‐filling and replacement method using N, N‐dimethylformamide (DMF) was employed to preserve the aerogel's porous structure during processing. By systematically varying TPU concentration (15%–25%), TPU/SAP ratio, and coating thickness (35–55 μm), the effects on thermal conductivity, mechanical durability, water repellency, and comfort were investigated. Results showed that DMF pre‐filling effectively prevented TPU infiltration into aerogel pores, improving insulation efficiency. Optimal performance was achieved at 20% TPU, a 7:3 TPU/SAP ratio, and a 55 μm thickness, yielding a low thermal conductivity of 0.1043 W m −1 K −1 , a water contact angle of 112°, and an air permeability of 7.68 mm/s. After five washing cycles, the fabric retained good insulation properties with only a 3.3% increase in thermal conductivity and a 13.2% reduction in peel strength. These findings demonstrate the feasibility of TPU/SAP/DMF coatings for durable, breathable, and thermally insulating textile applications.