Rice University materials scientists have created a light foam from two-dimensional sheets of hexagonal-boron nitride (h-BN) that absorbs carbon dioxide.
They discovered freeze-drying h-BN turned it into a macro-scale foam that disintegrates in liquids. But adding a bit of polyvinyl alcohol (PVA) into the mix transformed it into a far more robust and useful material.
The foam is highly porous and its properties can be tuned for use in air filters and as gas absorption materials, according to researchers in the Rice lab of materials scientist Pulickel Ajayan.
Their work appears in the American Chemical Society journal ACS Nano.
The polyvinyl alcohol serves as a glue. Mixed into a solution with flakes of h-BN, it binds the junctions as the microscopic sheets arrange themselves into a lattice when freeze-dried. The one-step process is scalable, the researchers said.
“Even a very small amount of PVA works,” said co-author and Rice postdoctoral researcher Chandra Sekhar Tiwary. “It helps make the foam stiff by glueing the interconnects between the h-BN sheets – and at the same time, it hardly changes the surface area at all.”
Read More: New boron nitride foam soaks up carbon dioxide
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