Image Courtesy: Harvard SEAS
A team of researchers at Harvard University has transformed ordinary knitted fabric into a programmable material capable of switching between stable shapes, controlling electrical circuits, and even tracking a person’s movements. The breakthrough could pave the way for a new generation of wearable sensors, adaptive clothing, and soft robotic devices.
Scientists at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) developed machine-knitted textiles that harness a property known as multistability, allowing a structure to remain stable in multiple configurations until an external force causes it to snap into another shape. The findings were published in Advanced Functional Materials.
The research was led by Kausalya Mahadevan, now a postdoctoral associate at Harvard, working in the laboratory of Professor Katia Bertoldi. Rather than relying on molded plastics or specialized manufacturing techniques, the team demonstrated that conventional weft knitting, the same process widely used to make gloves and hats, can produce complex three-dimensional structures using only carefully selected yarns and stitch patterns.
The researchers achieved this by combining highly elastic yarns with a knitting technique called plating, which places different yarns on opposite sides of the fabric. The resulting textiles naturally curl into stable three-dimensional forms, much like the edges of a cut T-shirt roll inward. By arranging horizontal and vertical knitted stripes in different patterns, the team created fabrics that rapidly snap between multiple stable shapes while remaining securely locked in each position.
To demonstrate practical applications, the researchers integrated conductive yarn into the textiles, turning them into flexible electrical switches. One prototype illuminated or turned off an LED whenever the fabric changed shape, while another, worn around a knee or elbow, detected snapping motions with an Arduino to count a person’s steps. The team also created a reconfigurable lampshade containing three knitted switches, each controlling a different light color.
Because the fabrics were produced using standard industrial knitting machines, the technology could be scaled using existing manufacturing infrastructure rather than requiring specialized equipment. The researchers believe the approach could eventually enable comfortable wearable electronics that monitor movement, provide tactile feedback, or dynamically change shape, expanding the role of textiles in smart devices and soft robotics.
