China HKUST developed airgel insulation imitation polar bear hair
With hair of different humans or other mammals, polar bear hair is hollow. Enlarged under a microscope, each cavity structure hairs are present, such a hollow tubular structure not only reduces the density of the polar bear hair, but also help to reduce the thermal conductivity, heat diffusion barrier from the skin surface to the surrounding polar bear low-temperature environment, the design of new artificial insulation materials worth to follow. Led by Professor Yushu Hong of the University of Science and Technology of China research team, inspired by polar bear hair hollow structure, the development of a synthetic class of polar bear hair hollow tubes of carbon airgel (CTA) method, the carbon nanotube airgel performance superelastic and low thermal conductivity. Relevant research results to \”Biomimetic Carbon Tube Aerogel Enables Super-Elasticity and Thermal Insulation\” in the title, published on June 6 (Chem 2019, CHEMJOURNAL-D-19-00185R1) on \”chemistry.\” The first author of the paper for my school doctoral students Zhanhui Juan. 
FIG. 1. Preparation of of the CTA. (A) a polar bear hair structure; a schematic diagram (B), show a method of producing a one-dimensional line as a template CTA; (C) of FIG CTA transmission; (D) CTA 90% for the compression set, a compression million times of stress – strain curves; (E) CTA thermal infrared image deg.] C on a hot plate of 400, indicating good insulating capability. 
Figure 2. Characterization of CTA. Comparison of different material density (A); Comparative (B) a material of different thermal conductivity; (C) Comparison of different material response rate; (D) CTA in compression set under conditions changed to 30% of the compression of a million times mechanical property changes; (D) CTA 90% for the compression set, changes in compressive mechanical properties of ten thousand times. After millions of years of natural development and evolution, its rich structure and species worth learning and development. The team as a template using a one-dimensional line, airgel carbon nanotubes prepared by a template synthesis macroscale (FIG. 1). Because of its unique microstructure, so that the airgel material exhibits excellent light, heat, and mechanical hydrophobicEnergy (FIG. 2). The minimum density of up to 8 kg / m 3 , below the majority of the insulation material has been reported; its contact angle 146 o , at 56% relative humidity for 120 days and still maintain a substantially constant thermal conductivity; the inner diameter of the hollow carbon tube (35 nm) is much smaller than the mean free path of air (75 nm), the air in the heat transfer tube is hardly, and therefore the carbon aerogels tube glue having good thermal insulation properties, which is the lowest thermal conductivity of only 23 mW m -1 K -1 , lower than the thermal conductivity of the drying air. A three-dimensional network structure of the carbon airgel has a macro-scale tube, which has superelasticity, when the free fall of the steel ball falls on the small surface of the carbon airgel tube, high rebound velocity (1434 mm s -1 ), or one million times the compression of 90% compression strain even ten thousand times at 30% strain, carbon airgel pipe structure remains intact. The researchers also explored the properties as its associated piezoresistive sensors, ten thousand times the compression at 30% strain after its relative resistance value substantially constant. Such a hollow structure by the polar bears hair of inspiration tube synthesized new carbon airgel is expected to meet the demand for high performance materials under extreme conditions, such as light insulation material, elastomeric material or the like in the field of aerospace applications. The study was funded by the National Natural Science Foundation of Innovative Research Groups, the National Natural Science Foundation of China, cutting-edge science research projects Academy of Sciences, Chinese Academy of nano-science innovation center of excellence, Suzhou Nanotech center of collaborative innovation. Highlighted by Chemical & Engineering News, Physics World, Phys.Org, ScienceDaily, and Eurekalert. https://cen.acs.org/materials/nanomaterials/Polar-bears-inspire-strong-elastic/97 /i23https://physicsworld.com/a/polar-bears-inspire-insulating-aerogel / https: //www.eurekalert.org/pub_releases/2019-06/cp-apm052919.phphttps: //www.sciencedaily.com/releases/2019/06/190606150317.htmhttps: // phys. org / news / 2019-06-polar-bear-inspired-material-insulation.html (Hefei national Research Center for Science, College of Chemistry and materials Science, Chinese Academy of nano-science innovation center of excellence, collaborative nanotechnology innovation center in Suzhou, Ministry of Research)
