Engineers at Harvard's John A. Paulson School of Engineering and Applied Sciences have found a way to make ordinary knitted fabric snap between multiple stable three-dimensional shapes, then wired that snapping motion into working electronic switches, according to research the school published this month in the journal Advanced Functional Materials.
The team relied on off-the-shelf industrial knitting machines and highly elastic yarns, rather than embedded electronics or exotic materials, to produce the effect. Using a technique called plating — placing different yarns on opposite faces of the fabric — combined with systematic patterns of horizontal and vertical knit stripes, the researchers produced dense, thick knits that curl naturally into three-dimensional forms and lock into two or more distinct configurations, a property physicists call multistability. The fabric behaves something like a light switch, holding whichever shape it is flipped into rather than springing back to flat.
From lampshades to step counters
By knitting conductive yarn into the structure, the team turned the shape-changing fabric into a soft electronic switch. Prototypes described in coverage of the research included a reconfigurable lampshade whose multistable switches correspond to different light colors, and fabric patches capable of counting steps or responding to movement, all without rigid sensors sewn into the cloth.
Because the effect comes entirely from yarn selection and knitting structure, the researchers say the approach could scale using standard textile manufacturing equipment already common across the clothing industry, rather than requiring specialized fabrication lines. That distinguishes it from many "smart textile" projects that depend on rigid or brittle components layered onto fabric, components that tend to degrade with washing and everyday wear.
The Harvard team said potential applications range from wearable sensors and adaptive clothing to soft robotics and reconfigurable home furnishings, though the current prototypes remain lab demonstrations. Researchers said next steps include testing durability through repeated washing and stretching cycles, and exploring whether the multistable structures can be tuned to snap in response to heat or moisture rather than only manual force.