Stay warm or cool with interwoven thread-like pumps in clothing

Researchers at EPFL research institute in Switzerland developed a pump in the form of a fibre, which can be woven directly into fabric to create clothing that can keep the wearer warm or cool.

While similar technologies based on pumping fluid are available, but these need large and noisy pumps, which are not suitable to integrate into clothing. The researchers solved this issue by integrating the pump into the fibre.

The invention uses a principle called charge injection electrohydrodynamics (EHD) to generate a fluid flow without any moving parts. Two helical electrodes embedded in the pump wall ionize and accelerate molecules of a special non-conductive liquid. The ion movement and electrode shape generate a net forward fluid flow, resulting in silent, vibration-free operation, and requiring just a palm-sized power supply and battery.

To achieve the pump’s structure, the researchers developed a fabrication technique that involves twisting copper wires and polyurethane threads together around a steel rod, which are then fused with heat. When the rod is removed the 2mm fibres can be integrated into textiles using standard weaving and sewing techniques.

The materials required are cheap and readily available, and the manufacturing process can be easily scaled up. Because the amount of pressure generated by the pump is directly linked to its length, the tubes can be cut to match the application, optimizing performance while minimizing weight. The robust design can also be washed with conventional detergents.

Photos: LMTS EPFL via EurekAlert