Polar bear hair inspires nanotechnology enhanced thermal textile

(Nanowerk News) Inspired by the microstructure and thermal insulation function of the polar bear hair, scientists have used a freeze-spinning technique to continuously fabricate silk fibroin solution into a fiber with aligned porous microstructure.
The textile woven with the biomimetic fibers has an excellent thermal insulation, active electroheating capacity when doped with carbon nanotubes (CNTs), good wearability and breathability, making it a promising material for thermal insulation and personal thermal management.
This work by researchers at Zhejiang University in China has been reported in Advanced Materials ("A Thermally Insulating Textile Inspired by Polar Bear Hair").
Polar bear hair inspires thermal textile
Polar bear hair with hollow core and aligned shell, and continuous and large-scale fabrication of biomimetic porous fiber. a) Photograph of a polar bear. b,c) SEM images showing the hollow core and aligned shell of a polar bear hair, respectively. d) Schematic illustration of the “freezespinning” technique, combining “directional freezing” with “solution spinning” to realize continuous and large-scale fabrication of biomimetic fibers with aligned porous structure, mimicking the polar bear hair. The silk fibroin solution extruded from a pump-controlled syringe is gradually frozen when it passes through a cold copper ring. Collected by a motor, the frozen fiber is further freeze-dried to reserve its porous structure and subsequently woven into a textile. e) Optical image showing a porous fiber collected in a roll. f,g) Optical (f) and SEM (g) images showing a woven textile of biomimetic porous fiber. The fiber diameter is around 200 µm. (© Wiley-VCH Verlag) (click on image to enlarge)
The team uses a freeze-spinning method to realize continuous and large-scale fabrication of fibers with aligned porous structure, mimicking polar bear hairs, which is difficult to achieve by other methods.
Textile woven with such biomimetic fibers shows an excellent thermal insulation property as well as good breathability and wearability.
In addition to passively insulate heat loss, the textile could also function as a wearable heater, when doped with electroheating materials such CNTs, to induce fast thermal response and uniform electroheating while maintaining its soft and porous nature for comfortable wearing.
Michael Berger By – Michael is author of three books by the Royal Society of Chemistry:
Nano-Society: Pushing the Boundaries of Technology,
Nanotechnology: The Future is Tiny, and
Nanoengineering: The Skills and Tools Making Technology Invisible
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