Biomimetic Cilia-Patterned Rubber Electrode Using Ultra Conductive Polydimethylsiloxane

In this paper, a biomimetic cilia-patterned flexible electrode using ultra conductive polydimethylsiloxane (PDMS) is presented. Due to the flexibility and cilia patterns, the developed electrode can have conformal contact with the human skin without interruptions of hair and rough skin. The conductive PDMS is prepared by mixing PDMS prepolymer and curing agent with Ag particles at different ratios. The performance of the best composite-made ciliated electrode is evaluated under different skin-like physical environments, and compared to the nonciliated flat electrode. For a typical flat electrode, hair and rough surface of the human skin disturb electrical contact, increasing contact impedance, whereas flexible ciliary structures of the proposed electrode show significantly improved conductivity passing through the furs to penetrate well into the gap on the alloyed skin, thus increasing the contact areas. Furthermore, bio-signal measurement using rigid metal electrodes suffers from motion artifacts causing signal errors due to bodily movement, which is remarkably addressed by ciliated flexible electrode. Therefore, the proposed electrode is applied to recording electrocardiography signal and compared with signal measured with conventional metal electrode, which showed about 20% enhancement than that of metal counterpart in identifying electrical activity of heart muscle of a person, as point-of-care clinical applications.