Fabric-Templated Co-Deposition of Nanofiber-Reinforced Composite Films with Ordered Surface Arrays for Ultrasensitive Wearable Sensing.

Fabricating polymeric films with ordered surface microarrays is of great significance for wearable sensing applications, yet it remains challenging to achieve scalable, cost-effective, and biocompatible architectures. Herein, we report a fabric-templated co-deposition strategy to construct nanofiber-reinforced composite films with well-ordered surface arrays. The approach utilizes woven cotton fabrics as soft templates, where capillary action directs the deposition of chitosan/poly (vinyl alcohol-co-ethylene) nanofiber mixtures within the microscale grooves, enabling direct replication of the array patterns after solvent evaporation and alkaline crosslinking. The resulting films exhibit hierarchical microstructures with uniform nanofiber distribution, strong hydrogen-bonding interactions, and tunable surface topographies. The optimized composite (Chit/NF1.5) achieves well-defined ordered surface arrays, enhanced mechanical flexibility, and stable structural integrity. After surface metallization, the array-patterned films demonstrate a piezoresistive sensing performance, with a 2.6-fold enhancement in current variation and a 3.4-fold higher sensitivity particularly in a low-stress region (0-0.15 N) compared to flat films. A dual-mechanism response involving contact-area enlargement at large strains and nanofiber-mediated conductive pathway formation at small strains is proposed to explain the ultrasensitivity. This work provides a versatile and scalable route for engineering ordered surface architectures, holding great promise for wearable health monitoring, smart electronics, and biomedical devices.