The advance from David Wirth, Jonathan Pokorski and colleagues University of California, San Diego overcomes a limitation of 3D printing that requires finished parts to be smaller than the machine making them.
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Tests on different resin formulations led the team to one that allowed them to print an object that expanded when exposed to heat.
According to the American Chemical Society, they used this formulation to 3D print a hollow, latticed sphere. When heated in an oven, a volatile component of the resin bubbles out as a gas leading to a porous, polystyrene foam-like material that was up to 40 times larger in volume than the original printed object.
As seen in the video, the team printed a boat, which could carry about 20 times more weight at its expanded size, and a wind turbine that could produce a small amount of electricity at its larger size.
Practical applications for the material could include cushioning, airfoils, buoyancy aids or expandable habitats for astronauts. Their findings are published in ACS Applied Materials & Interfaces.
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