Flexible PDMS electrode for one-point wearable wireless bio-potential acquisition

• We successfully proposed a one-point, wireless acquisition device to record ECG by using bio-compatible FPDEs on a human body.
• Increasing Au adhesion strength on the PDMS surface by CO2 laser technology.
• The proposed polyimide film tape functions as a mask to provide a convenient and inexpensive means of defining a metal pattern on the PDMS substrate without a thermal crosslink effect.
• The FPDE is more comfortable and suitable to contact with skin for ECG measurement than wet electrode.

This work presents a flexible poly-dimethylsiloxane (PDMS) electrode for a one-point, wearable, wireless bio-potential acquisition device. The proposed device measures electrocardiogram (ECG) signals and removes cumbersome wires from a general ECG monitoring system. A novel flexible PDMS dry electrode (FPDE) is constructed with Au as a contact layer in bio-compatible with skin and PDMS. However, PDMS has exhibited stability limit in Au deposition and patterning. This limitation is solved by the surface treatment of PDMS via CO2 laser to increase surface roughness from nm to μm scale. The laser treatment method can increase the adhesion ratio by up to 57% (max.), subsequently allowing for Au to be stably adhered on PDMS by physical deposition and patterning. This work also develops a simple technology to fabricate FPDEs by adopting polyimide film as the mask made with CO2 laser capable of reducing cost and reusable for metal patterning applications. Furthermore, a front-end acquisition circuit and a wireless ZigBee module are integrated and packaged by flexible and transparent PDMS cover with three-pad FPDEs into a novel one-point, wearable, wireless ECG acquisition device. Importantly, the proposed device can obtain ECG signals efficiently with comfortable skin touch.