Scientist developing self-healing biorenewable polymers
By Ben Coxworth
Materials that can repair themselves are generally a good thing, as they increase the lifespan of products created from them, and reduce the need for maintenance. Biorenewable polymers are also pretty likable, as they reduce or even eliminate the need for petroleum products in plastic production, replacing them with plant-derived substances. Michael Kessler, an Iowa State University associate professor of materials science and engineering, and an associate of the U.S. Department of Energy’s Ames Laboratory, is now attempting to combine the two.
Self-healing materials generally incorporate microcapsules containing a liquid healing agent, and catalyst elements, which are embedded within the material’s matrix. As cracks form within the matrix, the microcapsules rupture, releasing the healing agent. As soon as that agent encounters the catalyst, it hardens into three-dimensional polymer chains, thus filling and securing the cracks. Such technology has been used not only to create self-healing plastics, but also self-healing concrete.
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Superstrong metallic glass developed
By Jude Garvey
It seems hard to believe that glass could be stronger than steel, but a team of researchers has developed a super-strong metallic glass that has incredible plasticity when placed under stress, making it as strong and tough as metal. Typically, the structure of glass is strong but brittle which can cause cracks to develop and spread. The new metallic glass features palladium which has a high “bulk-to-shear” stiffness ratio. This allows the metallic glass to bend rather than crack – giving it a fracture toughness that goes beyond the limits of some of the strongest and toughest materials known.
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'Liquid pistons' – the next phone camera revolution?
By Darren Quick
Researchers at Rensselear Polytechnic Institute have developed "liquid pistons" that could be suited to a variety of applications. Using electromagnets the liquid pistons, which are highly tunable, scalable and have no solid moving parts, can function as pumps for lab-on-a-chip systems or could be used for adaptive lenses in future mobile phone cameras and implantable lenses.
The device consists of two drops of ferrofluid liquid, which are saturated with metal nanoparticles, situated in two holes in a substrate about the size of a piece of chewing gum. The entire device is situated in a chamber filled with water and pulses from an electromagnet are used to make one of the droplets – the driver – vibrate back and forth.