MISSOURI, US: Polymeric aerogels are nanoporous structures that combine some of the most desirable characteristics of materials, such as flexibility and mechanical strength. It is nearly impossible to improve on a substance considered the final frontier in lightweight materials.
But chemists from Missouri University of Science and Technology (Missouri S&T) have done just that by making aerogels that have rubber-like elasticity and can remember their original shapes.
Aerogels are created by replacing liquids with gases in a silica, metal oxide or polymer gel. They are used in a wide variety of products, from the insulation of offshore oil pipelines to NASA space missions.
The research is published in the journal Chemistry of Materials.
“The specific kind of polyurethane aerogels we have created are super elastic, meaning that they can be bent in any direction or be smashed flat and still return to their original shape,” said Dr Nicholas Leventis, lead researcher on the project and curators’ distinguished professor of chemistry at Missouri S&T.
“Our super elastic aerogels are different from rubber in that they can on-command return to a specific form. That is, they also show a strong shape memory effect, meaning that they can be deformed and cooled and keep the deformed shape forever., he added.
“However, when the temperature rises back to room temperature, they recover their original un-deformed shape. The shape memory effect is not new. Shape memory metallic alloys and polymers are known for many years; however, shape memory aerogels are the last frontier in lightweight,” Leventis explained.
Leventis and his group have demonstrated this unique property by shaping a “bionic hand” that is capable of mimicking coordinated muscle functions. When stimulated by heat, the aerogel and can close from its open-palm state and grab a pen.
“We believe this work has produced one of the ‘holy grails’ in the field of aerogels,” said Leventis. “I see a lot of biomimetic applications for these aerogels in the future. Their flexibility, combined with elasticity, greatly enhance the range of possible uses.”
Working with Leventis at S&T are Dr Chariklia Sotiriou-Leventis, professor of chemistry, and graduate students Suraj Donthula, Chandana Mandal, and Adnan Malik Saeed, and summer interns Theodora Leventis and James Schisler.
The work was supported by the US Army Research Office, and partial support was also provided by BASF Polyurethanes GmbH.
© Missouri S&T News
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