Bendable gadgets and electronics that are strong enough to be played around with, have been the talk-of-the-town for a long time now. Mobile phones, tablets, laptops that could freely bend as per our will without getting split into two seem like the equipment out of a Sci-Fi story. It is something that clumsy people like me have been desperately waiting for.
Researchers have been putting incessant efforts to develop *aerogels in hopes to fulfill both these requirements, that is, the flexibility and the resilience due to the fact that aerogels are light and porous, making them suitable a candidate but nothing of substance has been accomplished as of yet.
Aerogels are solids that are produced by replacing the liquid component of a gel with gas. These are low-density solids with high porosity, and several other properties, such as thermal insulation.
However, a new development at Zhejiang University, China, reported in the ACS Nano (American Chemical SocietyNano) uncovered an interesting truth. A team of researchers inspired by the “powdery” stem structure of the alligator-flag plant ( Thalia dealbata), has developed a special kind of aerogel. This plant is lean yet sturdy and can withstand extreme climatic conditions including rough winds (during which it bends but does not break), hence becoming an ideal choice for the team to base their research on.
To create this new type of *biomimetic *graphene aerogel, a bidirectional freezing technique was utilized which was solely developed for the purpose of its assembly. A bidirectional freezing technique is that in which the freezing would take place from two controlled directions in a controlled manner.
Biomimetic refers to something synthetic that mimics biochemical processes.
Graphene is an atom-thick carbon allotrope that is conductive in nature.
The stem of the alligator-flag plant is naturally porous, lightweight and resilient, owing to its three-dimensional structure, with interconnected*lamellar layers.
Lamella (pl. lamellae) is a thin, membrane-like fold in a chloroplast.
Inspired by this lamellar structure, the team took sheets of graphene oxide (GO) and froze them with the bidirectional freezing technique, assembling them into a similar architecture to that of the plant. Successive*freeze-drying and *thermal reduction led to the formation of graphene aerogels with 3D architectures that are highly tunable, and could further lead to the desired results.
Freeze-drying takes place by rapidly freezing an object and then subjecting it to a vacuum to remove ice deposition by sublimation.
Thermal Reduction is a heating process used to reduce a compound, that is, to make a compound lose oxygen (or add hydrogen, depending on the scenario). In this scenario, Graphene oxide is reduced by thermal reduction.
Later, it was found out on testing that this newly formed material could support and endure 6000 times its own weight, could withstand excessive compression and still remain resilient.
To test its electrical conductivity, they put the aerogel in a circuit containing an LED, verifying that it could work as a component for electronic gadgetry.
Flexible electronic gadgets; that won’t break due to shock if you drop them; you wouldn’t have to worry about placing them in cushioned areas while packing them in your traveling bags or in your pockets.
The researchers are of the opinion that these graphene aerogels could be useful for mechanically switchable electronics; also, that the approach would be helpful in improving other types of materials in future.
Bai et al. Biomimetic Architectured Graphene Aerogel with Exceptional Strength and Resilience. ACS Nano, June 2017 DOI: 10.1021/acsnano.7b01815