Biomimetic 4D reconstruction of textile waste: printable heat-humidity co-responsive smart fabric

The high-value reuse of textile waste is essential for the sustainability of the textile industry; however, it remains a significant challenge, particularly regarding smart materials, despite numerous reports on textile waste recycling methods. 4D printing, as an advanced technological tool, can incorporate smart attributes to enhance the competitiveness of textile waste market. Here, we present a novel strategy of biomimetic 4D reconstruction of textile waste, in which 4D-printed heat-humidity co-responsive fabrics integrate a humidity-responsive substrate derived from textile wastes and heat-responsive components. The humidity-responsive materials consist of regenerated polyurethane substrate from spandex tarpaulin waste and regenerated cellulose fillers from cotton-knitted fabric waste. The heat-responsive component is based on polycaprolactone photo-crosslinked with benzophenone and triallyl isocyanurate. The printed structures can be programmed for preset actuation, and the 4D-printed heat-humidity co-responsive fabrics can be activated in wet, hot, or wet-hot environments, conducive to maintaining heat-humidity comfort of the human body. Our research offers innovative solutions for repurposing textile waste recyclable products, and the 4D smart fabrics would provide strong candidates in personal thermal-moisture management.