Polymer-based Sealant Material Enables New Soft Robotics Invention

Posted on 4/6/2021 10:58:25 AM By Slash Gear

Taking their cue from plants like the Venus Flytrap and some animals, which rapidly respond to any changes in their environment, scientists have developed an intelligent pressure and stretch-sensitive soft sealant material which can react in a similar way by curling or uncurling when under pressure or mechanical strain, and expand when stretched.

The new sealant based material, according to the research team, is aimed at being adaptable for use in soft robotics which carry out complicated tasks and locomotion. Unlike the current approach, it does not need an external computer, or the integration of bulky sensors and moving parts.

Instead, the researchers report, the material makes use of thin and flexible liquid metal printed circuits which are integrated with liquid crystal elastomers, polymers that can respond to large shape changes when heated or cooled, in order to create a material which produces heat in response to generated electric current or pressure applied by the circuit, and cools down when the current drops.


The team reports that certain benefits of the nature-base response were revealed in tests.   Among these was that applying a nickel-infused gallium-indium alloy onto the liquid crystal elastomer made it possible to magnetically move the liquid metal in the lines to form an uninterrupted circuit. 

In testing the soft material’s ability to curl and uncurl, a color-changing silicone sealant film which darkens from pink to red when exposed to heat, continued to darken showing increased heat levels, as a soft material being tested for use in the development of autonomous grippers capable of perceiving and responding to pressure or stretching applied to the circuits, started to curl increasingly.

This soft material, the team reports, showed positive results in the team’s ability to  use the grippers to pick up small round objects and drop them when either pressure was released or the material was stretched. For testing uncurling abilities, the team used the same sealant film, and applied pressure to the circuit at the base of a spiral. As the pressure and temperature rose the soft material used a rotating motion to unfurl the film.