New worm-inspired material adapts to its environment

Inspired by a sand worm, scientists have developed a new bio gel material which changes shape in response to its environment and could help control movements of soft robots.
The protein material designed and modelled by researchers, including those from Massachusetts Institute of Technology (MIT) in the US, expands and contracts based on changing pH levels and ion concentrations.
It was developed by studying how the jaw of Nereis virens - a sand worm, forms and adapts in different environments, researchers said.
The resulting pH- and ion-sensitive material is able to respond and react to its environment.
Understanding this naturally-occurring process can be particularly helpful for active control of the motion or deformation of actuators for soft robotics and sensors without using external power supply or complex electronic controlling devices, researchers said.

"The ability of dramatically altering the material properties, by changing its hierarchical structure starting at the chemical level, offers exciting new opportunities to tune the material, and to build upon the natural material design towards new engineering applications," said Markus J Buehler of MIT.

The research shows that depending on the ions and pH levels in the environment, the protein material expands and contracts into different geometric patterns.
When the conditions change again, the material reverts back to its original shape.
This makes it particularly useful for smart composite materials with tunable mechanics and self-powered roboticists that use pH value and ion condition to change the material stiffness or generate functional deformations, researchers said.

The study was published in the journal ACS Nano.