Researchers at The Ohio State University have embroidered circuits into fabric with 0.1 mm precision -- an ideal size for integrating sensors and electronic components into clothing. The achievement supports the development of new wearable technology, including a bandage that monitors tissue or a flexible fabric cap that senses brain activity.
The functional textiles, also called “e-textiles,” are created in part on a typical tabletop sewing machine. The machine automatically embroiders thread into fabric, based on a pattern loaded via a computer file. The researchers substitute the thread with fine silver metal wires that, once embroidered, feel the same as traditional clothing materials.
Previously, the researchers had used silver-coated polymer thread with a 0.5-mm diameter, each thread made up of 600 even finer filaments twisted together. The new threads have a 0.1-mm diameter, made with only seven filaments. Each filament is copper at the center, enameled with pure silver.
Tests showed that an embroidered 6-inch-across spiral antenna transmitted signals at frequencies of 1 to 5 GHz with near-perfect efficiency. The antenna could be used to send signals and health data to mobile devices.