Ultralight and superelastic ultrafine fiber-based sponges by carding process for high-performance warmth retention

In winter, human body needs to wear clothing to prevent heat loss to ensure physical and psychological health. Traditional warmth retention materials have large diameter, resulting in large pore size and low porosity, so it is difficult to store static air and shows poor warmth retention performance. Ultrafine fibers with small diameter are expected to provide high-performance warmth retention materials, but always suffer from poor mechanical properties. Herein, a strategy of mixing ultrafine fibers with microfibers of different scales to prepare fiber sponges with both robust mechanical properties and effective warmth retention performance by carding process is proposed. By adjusting different fiber ratios, ultrafine fiber-based sponges with remarkable comprehensive performances are obtained. They exhibit nearly full recovery after 500 tensile cycles and 1000 compression cycles, and their thermal resistance could reach up to 0.57 m2·K·W−1. This work is of great significance for the large-scale use of ultrafine fibers to fabricate high-performance warmth retention materials.