Microscopic tears in a new kind of man-made material may actually help the substance bulk up like a bodybuilder at the gym.
“We’ve shown how normally destructive mechanical forces can be channeled to bring about stronger materials,” said Duke chemist Steve Craig, who led the research. “The material responses are like Silly Putty transforming into a solid as stiff as the cap of a pen or a runny liquid transforming into soft Jell-O.”
Scientists could one day use the stress-induced strength from these new materials to make better fluids such as engine oil, or soft-structure substances such as artificial heart valves. Materials like this wear out over time because of the repeated mechanical forces they experience during use. But Craig said if a material had properties to slow down its destruction, it would greatly improve quality of life.
It is the first time scientists have used force-induced chemistry within a material to make it stronger in response to stress. The results appear Monday, Aug. 5, 2013, inNature Chemistry.
In past experiments, Craig’s team has gripped and tugged on individual molecules of a material to see how it reacted at the atomic level. Now, the scientists have scaled up the material to contort it macroscopically and see how it responds.
Craig said the response is similar to what happens when a person lifts weights. Those individual stresses trigger biological processes in the muscles that ultimately increase the person’s strength.
“It’s the same idea chemists would like to use for synthetic materials,” he said. “Everyday materials can wear out with repeated stress. Think of your favorite t-shirt or even the oil in your car engine. Wear after wear, fire after fire, these materials break down.”
Read more at: Phys.org