Stretchable and resilient fibrous sponges tailored by interlocking double-network for warmth retention

Developing high-performance warmth retention materials to protect humans from the harm causing by extra cold conditions is remained challenging. Herein, we firstly fabricate fibrous sponges tailored by interlocking double-networks to serve as novel warmth retention materials. Polymethyl methacrylate (PMMA) microfibers build the three-dimensional (3D) skeleton and polyurethane (PU) nanofibers are introduced into the skeleton to improve the mechanical property and warmth retention. The PMMA/PU fibrous sponge (PMMA/PUFS) has a high tensile stress of 159.02 kPa, large tensile elongation of 65.85%, and good resilience after bearing nearly complete deformation, as well as ultralight property (7.38 mg cm−3) and effective warmth retention (25.28 mW m−1 K−1). The successful fabrication of PMMA/PUFS may provide a new vision for creating functional materials with good mechanical properties.