Nav: Home

A polar-bear-inspired material for heat insulation

June 06, 2019

For polar bears, the insulation provided by their fat, skin, and fur is a matter of survival in the frigid Arctic. For engineers, polar bear hair is a dream template for synthetic materials that might lock in heat just as well as the natural version. Now, materials scientists in China have developed such an insulator, reproducing the structure of individual polar bear hairs while scaling toward a material composed of many hairs for real-world applications in the architecture and aerospace sectors. Their work appears June 6 in the journal Chem.

"Polar bear hair has been evolutionarily optimized to help prevent heat loss in cold and humid conditions, which makes it an excellent model for a synthetic heat insulator," says co-senior author Shu-Hong Yu, a professor of chemistry at the University of Science and Technology of China (USTC). "By making tube aerogel out of carbon tubes, we can design an analogous elastic and lightweight material that traps heat without degrading noticeably over its lifetime."

Unlike the hairs of humans or other mammals, polar bear hairs are hollow. Zoomed in under a microscope, each one has a long, cylindrical core punched straight through its center. The shapes and spacing of these cavities have long been known to be responsible for their distinctive white coats. But they also are the source of remarkable heat-holding capacity, water resistance, and stretchiness, all desirable properties to imitate in a thermal insulator.

"The hollow centers limit the movement of heat and also make the individual hairs lightweight, which is one of the most outstanding advantages in materials science," says Jian-Wei Liu, an associate professor at USTC. To emulate this structure and scale it to a practical size, the research team--additionally co-led by Yong Ni, a mechanical engineering professor at USTC--manufactured millions of hollowed-out carbon tubes, each equivalent to a single strand of hair, and wound them into a spaghetti-like aerogel block.

Compared to other aerogels and insulation components, they found that the polar-bear-inspired hollow-tube design was lighter in weight and more resistant to heat flow. It was also hardly affected by water--a handy feature both for keeping polar bears warm while swimming and for maintaining insulation performance in humid conditions. As a bonus, the new material was extraordinarily stretchy, even more so than the hairs themselves, further boosting its engineering applicability.

Scaling up the manufacturing process to build insulators on the meter scale rather than the centimeter one will be the next challenge for the researchers as they aim for relevant industrial uses. "While our carbon-tube material cannot easily be mass produced at the moment, we expect to overcome these size limitations as we work toward extreme aerospace applications," says Yu.
-end-
This work was supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences, and the National Basic Research Program of China.

Chem, Zhan et al.: "Biomimetic Carbon Tube Aerogel Enables Super-Elasticity and Thermal Insulation" https://www.cell.com/chem/fulltext/S2451-9294(19)30202-5

Chem (@Chem_CP) is the first physical science journal published by Cell Press. A sister journal to Cell, Chem, which is published monthly, provides a home for seminal and insightful research and showcases how fundamental studies in chemistry and its sub-disciplines may help in finding potential solutions to the global challenges of tomorrow. Visit: http://www.cell.com/chem. To receive Cell Press media alerts, contact press@cell.com.

Cell Press

Related Carbon Articles:

Can wood construction transform cities from carbon source to carbon vault?
A new study by researchers and architects at Yale and the Potsdam Institute for Climate Impact Research predicts that a transition to timber-based wood products in the construction of new housing, buildings, and infrastructure would not only offset enormous amounts of carbon emissions related to concrete and steel production -- it could turn the world's cities into a vast carbon sink.
Investigation of oceanic 'black carbon' uncovers mystery in global carbon cycle
An unexpected finding published today in Nature Communications challenges a long-held assumption about the origin of oceanic black coal, and introduces a tantalizing new mystery: If oceanic black carbon is significantly different from the black carbon found in rivers, where did it come from?
First fully rechargeable carbon dioxide battery with carbon neutrality
Researchers at the University of Illinois at Chicago are the first to show that lithium-carbon dioxide batteries can be designed to operate in a fully rechargeable manner, and they have successfully tested a lithium-carbon dioxide battery prototype running up to 500 consecutive cycles of charge/recharge processes.
How and when was carbon distributed in the Earth?
A magma ocean existing during the core formation is thought to have been highly depleted in carbon due to its high-siderophile (iron loving) behavior.
New route to carbon-neutral fuels from carbon dioxide discovered by Stanford-DTU team
A new way to convert carbon dioxide into the building block for sustainable liquid fuels was very efficient in tests and did not have the reaction that destroys the conventional device.
How much carbon the land can stomach with more carbon dioxide in the air
Researchers from 28 institutions in nine countries succeeded in quantifying carbon dioxide fertilization for the past five decades, using simulations from 12 terrestrial ecosystem models and observations from seven field carbon dioxide enrichment experiments.
'Charismatic carbon'
According to the Intergovernmental Panel on Climate Change (IPCC), addressing carbon emissions from our food sector is absolutely essential to combatting climate change.
Extreme wildfires threaten to turn boreal forests from carbon sinks to carbon sources
A research team investigated the impact of extreme fires on previously intact carbon stores by studying the soil and vegetation of the boreal forest and how they changed after a record-setting fire season in the Northwest Territories in 2014.
Can we still have fun if the UK goes carbon neutral?
Will Britain going carbon neutral mean no more fun? Experts from the University of Surrey have urged local policy makers to put in place infrastructure that will enable people to enjoy recreation and leisure while keeping their carbon footprint down.
Could there be life without carbon? (video)
One element is the backbone of all forms of life we've ever discovered on Earth: carbon.
More Carbon News and Carbon Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.