Direct Printing of Conducting Polymers on Fabrics for Smart Bandage Manufacturing

Bandages are essential for wound care, but chronic wounds require prolonged treatment and frequent bandage changes, which can cause discomfort and disrupt healing. Since skin conditions reflect wound status, integrating flexible electronics into bandages offers a noninvasive way to monitor healing. PEDOT:PSS, with its excellent electrical, chemical, and mechanical properties, is well suited as a flexible electronic material for such applications. Direct ink writing (DIW), an extrusion-based additive manufacturing (AM) technique, enables customized electronics but faces challenges when printing on rough, porous substrates such as bandages, often resulting in geometrical defects and instability. The present study investigates the use of an electric field and laser irradiation, aiming to enable the deposition and solidification of conducting liquid ink on substrates, thereby fabricating intact conducting traces on rough bandages for sensing and monitoring. Experiments were conducted to investigate the effects of process parameters on the integrity of printed conductive polymer lines. The relationship between these parameters and the line integrity was analyzed to establish guidelines for selecting optimal conditions to enhance the printability. Additionally, the printed line width (∼100 μm) was evaluated and compared with that of commercial manufacturing processes, demonstrating enhanced resolution. Test cases involving various multilayer circuit designs were performed, and the electrical conductivity and temperature-sensing capabilities (with a temperature coefficient of resistance of approximately −0.3%/°C) were characterized and analyzed. The experimental results validated the effectiveness of the proposed technique for printing conducting polymer inks on rough textiles and previously deposited layers. This research opens novel avenues for manufacturing customized wearable circuits and sensors on rough, porous textiles such as bandages, with the potential to revolutionize patient monitoring.