DE material demonstrates artificial muscle potential

The team at Bristol University used its system to mimic the camouflage abilities of certain fish, which use surface muscles to shift around pigment.

To achieve these quick, flexible contractions, the team used a type of material called dielectric elastomers (DEs) — essentially elastic parallel-plate capacitors, which consist of one or more elastomeric dielectric film coated with compliant electrodes.

‘Direct competition might be something like hydraulics, pneumatics or electromagnetics,’ said Dr Jonathan Rossiter of Bristol. ‘All of those are either more complicated or heavier or require a certain scale — it’s very difficult to miniaturise them. With these materials you can make them large with desktop-sized devices or miniaturise them down to a few micrometres.’

Crucially, depending on the arrangement of DE stacks, the material can perform different functions such as radial expansion or diaphragm-type contraction activity.

In the study, two types of artificial chromatophores (muscular pigment cells) were created: the first based on a mechanism adopted by squids and the second based on a rather different mechanism adopted by zebrafish.