Superelastic and strong microfibrous sponges prepared by solution blow spinning for high-efficiency warmth retention

We report a facile strategy for preparing ultralight, mechanically robust, and washable heat-retaining materials via solution blow spinning technology and thermal crosslinking. Fluffy microfibrous assemblies with nonwoven structure were fabricated by blending fibers of stiff and soft polymers and creating a bonding architecture among them. The premise of this design is that polystyrene, which is stiff, can endow materials with rigidity, while thermoplastic polyurethane, which is soft, can absorb energy during mechanical deformation. Moreover, the stability of the sponge was improved by using tris (2-methyl-1-aziridine propionate; TTMA) as a crosslinking agent. The optimized microfibrous sponges present excellent mechanical properties with a large breaking elongation of 42.1% and outstanding resilience in resisting 100 cyclic compressions at 40% strain. Furthermore, the microfibrous sponges exhibit a low volume density of 33.32 mg/cm 3 , effective heat-preservation ability (low thermal conductivity: 23.1 mW/m·K) and excellent washability. The preparation of microfibrous sponges via solution blow spinning can be a novel route for developing ultralight and superelastic heat retention materials.