Researchers demonstrate a simple iron-on method for integrating stretchable, conductive circuits into shirts and other textiles.
Wearable electronics are becoming a big part of our world, moving beyond smartwatches and fitness bands into shirts, hats, and other clothing items. Consumers’ acceptance of wearable e-textiles ultimately depends on comfort qualities such as softness, stretch, and breathability, but embedding electronic circuits into soft, stretchy fabrics has proven challenging. Traditional approaches—such as coating fibers with conductive metals or weaving in liquid metal fibers—have made progress, yet many methods struggle to balance flexibility, durability, and ease of manufacturing. Many other ideas have been trialed, but there remains a need for approaches that simultaneously provide strong fabric integration, stretchability, and multifunctionality in reprocessable systems.
Iron-on components: a simple path to functional wearables
New work published in ACS Applied Materials & Interfaces describes an innovative technique: iron-on electronic patches made from liquid metal microdroplets embedded in a thermoplastic polyurethane (TPU) matrix. Developed by researchers at Virginia Tech, these patches can be heat-pressed onto a variety of fabrics using a standard household iron, forming a strong bond without sacrificing electrical conductivity.
The process starts with mixing microscopic droplets of a gallium-indium alloy into a TPU solution, which is then cast and dried into a thin, elastic sheet. This composite is both highly stretchable—up to 600% strain—and electrically conductive, with performance comparable to or better than many existing materials. Unlike other liquid metal circuits, these patches do not require a separate sintering step to activate conductivity, simplifying fabrication and integration.
To demonstrate the technology, the team created two prototypes: a university logo with embedded LEDs that stayed lit even when the fabric was folded or stretched, and a shirt with an ironed-on microphone that recorded sound across the full human hearing range. Both devices maintained reliable electrical connections to rigid components, even under repeated deformation.
Watch videos of the technology in action in the Supporting Information section of the research article.
Beyond clothing, this technology has potential applications in soft robotics, healthcare monitoring, and human-machine interfaces. The iron-on approach allows for rapid, robust integration of electronics into textiles, potentially enabling new forms of wearable devices that are comfortable, durable, and easy to manufacture. While further work is required to identify long-term durability and broader applications, this study marks a step forward in making wearable technology more accessible and adaptable.
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