Stretchable\nand Superelastic Fibrous Sponges Tailored\nby “Stiff–Soft” Bicomponent Electrospun Fibers\nfor Warmth Retention

Abstract

Health risks in an\nextremely cold environment make warm retention\nequipment highly desirable. However, creating materials with a high\nwarm retention performance and robust mechanical property to durably\nprevent against the harsh conditions is highly challenging. Herein,\nwe report on a one-step and facile strategy to fabricate stretchable\nand superelastic fibrous sponges by creating unique “stiff–soft”\npolymer networks within fibers and bonding architecture among fibers.\nThe premise of this design is that stiff polystyrene can endow materials\nwith rigidity and soft polyurethane can absorb energy during mechanical\ndeformation. Benefiting from this systematic tailoring for the polymer\nand assembling networks, the resultant fibrous sponges exhibit a unique\ntensile recovery property, a large breaking elongation of 70%, and\nan outstanding resilience for resisting 100 cyclic compressions with\n50% strain under −50 °C. Moreover, the fibrous sponges\npossess dramatic characteristics of high porosity (∼99.31%),\nultralight property (volume density = 7.68 mg cm^–3), and effective warmth retention (thermal conductivity = 27.6 mW\nm^–1 K^–1), as well as technical\nfeatures of the simple assembly process to scale up easily. The preparation\nof fibrous sponges provides a new vision for developing ultralight\nand efficient warmth retention materials.