What makes penguin feathers ice-proof?
Humboldt penguins live in places that dip below freezing in the winter,
and despite getting wet, their feathers stay sleek and free of ice. Research-
ers have now figured out what could make that possible. They report in
ACS’ Journal of Physical Chemistry C that the key is in the microstructure of
penguins’ feathers. Based on their findings, the researchers replicated the
architecture in a nanofiber membrane that could be developed into an
The range of Humboldt penguins extends from coastal Peru to the tip of southern Chile. Some
of these areas can get frigid, and the water the birds swim in is part of a cold ocean current that
sweeps up the coast from the Antarctic. Their feathers keep them both warm and ice-free.
Researchers had suspected that penguin feathers’ ability to easily repel water explained why
ice doesn’t accumulate on them: Water would slide off before freezing. But research has
found that under high humidity or ultra-low temperatures, ice can stick to even superhy-
drophobic surfaces. So, Jingming Wang and colleagues sought another explanation.
The researchers closely examined Humboldt penguin feathers using a scanning electron microscope. They found that the feathers were comprised of a network of barbs,
wrinkled barbules, and tiny interlocking hooks. In addition to being hydrophobic, this
hierarchical architecture with grooved structures is anti-adhesive. Testing showed that
ice wouldn’t stick to it. Mimicking the feathers’ microstructure, the researchers developed an icephobic polyimide fiber membrane. They say it could potentially be used in
applications such as electrical insulation.
Read more about the research: “Icephobicity of Penguins Spheniscus Humboldti and
So long lithium,
an Artificial Replica of Penguin Feather with Air-Infused Hierarchical Rough Structures,” The
Journal of Physical Chemistry C, 2016, Article ASAP.
As renewable energy sources grow, so does the
demand for new ways to store the resulting energy at low-cost and in environmentally friendly ways. Now researchers report
in ACS’ journal Environmental Science & Technology Letters a first-of-its-kind
development toward that goal: a rechargeable battery driven by bacteria.
Solar, wind, and other renewable energy sources are gaining ground as nations work to lower greenhouse gas emissions and reliance on petroleum. But sunlight and wind are not constant, so consumers can’t
count on them 24-7. Storing energy can make renewables more reliable, but current technologies such as
lithium-ion batteries are limited by safety issues, high costs, and other factors. Sam D. Molenaar and his colleagues from Wageningen University and Wetsus (The Netherlands) wanted to come up with a less expensive, sustainable solution.
Researchers combined, for the first time, two separate microbial energy systems: one that uses bacteria
to form acetate from electricity and one to convert the produced acetate back into electricity. Molenaar and
his team successfully charged the battery over a 16-hour period and discharged it over the next 8 hours,
mimicking the day-night pattern typical for solar energy production. They repeated this cycle 15 times in as
many days. With further optimization, they say the energy density of the microbial battery could be competitive with conventional technologies. Someday it could help us store energy from local renewable sources
safely and at a lower cost than current options.
Read more about the research: “Microbial Rechargeable Battery: Energy Storage and Recovery through
Acetate,” Environmental Science & Technology, 2016, 3 ( 4), pp 144–149.
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