New Synthetic Nanomaterial Gets Stronger After Repeated Stress

Researchers at Rice University have discovered an interesting property of a new synthetic material they’ve developed – repeated stress applied to this new polymer-based nanocomposite makes it stiffer.
Much in the same way that our bones get denser and our muscles get stronger after weightlifting, the new material, a mixture of polydimethylsiloxane (PDMS) and carbon nanotubes, measured a 12 percent increase in stiffness after being subjected to 3.5 million compressions over the course of a week.
Researchers are somewhat stumped at the reason for this phenomenon; polymers typically do not behave in this way, and the addition of carbon nanotubes doesn’t cause any chemical interactions. Moreover, unlike non-Newtonian fluids, the new material only stiffens under dynamic, repeated stress.
While there’s a lot to learn about this strange, rubbery polymer, its properties are already attractive as a possible replacement for cartilage. Such a material would be appealing as it could respond to the forces being applied to it but remain pliable in areas that are not being stressed.
Article from Rice University: Rice University lab creates self-strengthening nanocomposite
Abstract in ACS Nano: Observation of Dynamic Strain Hardening in Polymer Nanocomposites