Robotic fabrics or textiles are far from new, but they’re usually attached to bulky external machines that can modulate air pressure inside them to make them move or change their shape. Since that could limit their potential applications, a team of Harvard researchers got together to develop a textile-based soft robot that can regulate itself without being tethered to any machine.
The researchers from Harvard’s Wyss Institute for Biologically Inspired Engineering, John A. Paulson School of Engineering and Applied Sciences and Department of Chemistry and Chemical Biology come from various disciplines. They designed a robotic fabric called Smart Thermally Actuating Textiles (STATs), which is composed of tightly sealed pouches containing a fluid known as Novec 7000. When heated, the fluid vaporizes, and its volume expands up to 100-fold to change the fabric’s shape. But when it’s cooled, it condenses back to a liquid, thereby deflating the fabric.
To eliminate the need for an external machine, they weaved electronically-conductive silver-plated threads into the material they used for the STATs. The threads serve as the smart fabric’s heater and sensor elements, enabling the temperature and pressure changes needed to switch Novec 7000’s phase from liquid to vapor and vice versa. The study’s co-first author, Christopher Payne, explained:
“With an integrated ‘closed-loop feedback’ controller, STATs autonomously maintained their pressure even when placed into environments in which the exterior temperature fluctuates, like close to an air tube that actively cools the system.”
The researchers said they can manufacture the fabric in bulk and with arbitrary geometries, giving it a wide number of potential applications. It could be used in mechanotherapeutic wearables that could apply pressure on injuries and accelerate tissue repair, for instance. It could also be used in responsive cushions to help prevent bed and wheelchair sores, and perhaps even in the creation of dynamic garments for avant-garde fashion shows.