Rapidly self-healing, highly conductive, stretchable, body-attachable hydrogel sensor for soft electronics

Self-healing hydrogels are widely used in body-attachable sensors because they are stretchable, skin-friendly, highly sensitive, and mechanically strong. We developed a polyvinyl alcohol/poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PVA/PEDOT:PSS) hydrogel that responds rapidly and self-heals following external mechanical damage for use in body-attachable-sensor applications. The addition of ethylenediamine during hydrogel synthesis enhanced the crosslinking reaction and facilitated gelation. The hydrogel demonstrated a self-healing efficiency of 80 % and a gauge factor of 0.67 when strained in the 0-70 % range. The selfhealing sensor exhibited response and recovery times of less than 0.25 s, with a self-healing time of less than 5 min. The self-healing sensor was tested for bodily motions, such as finger pressure, bending, voice vibration, severe stretching at 70 % strain, and stretching for 1000 continuous cycles.