Friday, December 20, 2019

New insulator inspired by Polor Bear hair

Structure of Polor bear hair

Polor Bare in arctic circle
To survive in Arctic conditions, polar bears must rely on insulation supplied by their own fat, skin, and fur. For engineers, polar bear hair is an ideal template for synthetic mate­rials that could lock in heat just as ef­ficiently. Now, materials scientists at the University of Science and Technol­ogy of China (USTC) have developed such an insulator, reproducing the structure of individual hairs with the goal of building a material composed of many hairs for applications in archi­tecture and aerospace. Unlike the hair of other mammals, polar bear hair is hollow. Examined under a microscope, each one has a long, cylindrical core punched through its center. The shapes and spacing of these cavities are not only responsible for their distinctive white coats, but also the source of re­markable heat-holding capacity, water resistance, and stretchiness.

Construction of new insulator

To imitate this structure and scale it to a useful size, researchers manu­factured millions of hollowed-out car­bontubes, each equivalent to a single strand of hair, and wound them into a spaghetti-like aero­gel block. Compared to other aerogels, the new hollow-tube design is lighter weight and more resistant to heat flow, say researchers. The new material is also ex­traordinarily stretchy, even more than the hairs themselves, further boosting its usefulness. 
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