Large‐scalable polar bear hair‐like cellular hollow fibers with excellent thermal insulation and ductility.

Passive warm‐keeping textiles could reduce carbon emissions by turning down indoor heating in winter. Polar bear hair exhibits a unique structure composed of a hollow core and an aligned porous shell, which extremely helps to resist heat transport. Great interest has arisen in the development of thermo‐insulating textiles with this biomimetic structure. In this work, cellular hollow fibers were made by a large‐scalable wet spinning‐foaming process. This efficient method achieved rapid formation of polar bear hair‐like fiber as well as facile turning properties of the fibers. The structure and properties of biomimetic fibers depended on the content of foaming agent. As‐prepared porous thermoplastic polyurethane (TPU)/polyacrylonitrile (PAN) composited fiber showed excellent ductility. The maximum tensile strength and breaking elongation was 4.31 MPa and 121%, respectively. The corresponding woven textile exhibited excellent thermal insulation properties even under deformation by compression or tension. The temperature difference across the thickness of textile was 17.9 and 34.9°C under a background temperature of 0 and 80°C, respectively. It may pave the way to fabricate new structure–function integrated fiber materials for warm‐keeping textiles. [ABSTRACT FROM AUTHOR]