posted on 2023-01-03, 13:05authored bySehyun Park, Seunghyeb Ban, Nathan Zavanelli, Andrew E. Bunn, Shinjae Kwon, Hyo-ryoung Lim, Woon-Hong Yeo, Jong-Hoon Kim
Recent
advances in soft materials and nano-microfabrication have
enabled the development of flexible wearable electronics. At the same
time, printing technologies have been demonstrated to be efficient
and compatible with polymeric materials for manufacturing wearable
electronics. However, wearable device manufacturing still counts on
a costly, complex, multistep, and error-prone cleanroom process. Here,
we present fully screen-printable, skin-conformal electrodes for low-cost
and scalable manufacturing of wearable electronics. The screen printing
of the polyimide (PI) layer enables facile, low-cost, scalable, high-throughput
manufacturing. PI mixed with poly(ethylene glycol) exhibits a shear-thinning
behavior, significantly improving the printability of PI. The premixed
Ag/AgCl ink is then used for conductive layer printing. The serpentine
pattern of the screen-printed electrode accommodates natural deformation
under stretching (30%) and bending conditions (180°), which are
verified by computational and experimental studies. Real-time wireless
electrocardiogram monitoring is also successfully demonstrated using
the printed electrodes with a flexible printed circuit. The algorithm
developed in this study can calculate accurate heart rates, respiratory
rates, and heart rate variability metrics for arrhythmia detection.