Watch this paper doll do sit-ups thanks to new kind of “artificial muscle”

A new twist on lightweight organic materials shows promise for artificial-muscle applications. Chinese scientists spiked a crystalline organic material with a polymer to make it more flexible. They reported their findings in a new paper in ACS Central Science, demonstrating proof of concept by using their material to make an aluminum foil paper doll do sit-ups.

There’s a lot of active research on developing better artificial muscles—manmade materials, actuators, or similar devices that mimic the contraction, expansion, and rotation (torque) characteristic of the movement of natural muscle. And small wonder, since they could be useful in a dizzying range of potential applications: robots, prosthetic limbs, powered exoskeletons, toys, wearable electronics, haptic interfaces, vehicles, and miniature medical devices, to name just a few. Most artificial muscles are designed to respond to electric fields, (such as electroactive polymers), changes in temperature (such as shape-memory alloys and fishing line), and changes in air pressure via pneumatics.

Yet artificial muscles typically weigh more than scientists would like and don’t respond as quickly as needed for key applications. So scientists are keen to develop new types of artificial muscle that are lightweight and highly responsive. Just this past week, Science featured three papers from different research groups (at MIT, University of Texas at Dallas, and University of Bordeaux) describing three artificial-muscle technologies based on tiny twisted fibers that can store and release energy.