Institute of Chemistry, Academia Sinica – Research

Sensitive pressure sensors with easy fabrication and stable performance are essential for next-generation wearable electronics. Incorporating hydrogels into pressure sensors offers enhanced wearability owing to their soft, flexible, and skin-conformable nature. In this study, we developed a monolithic Janus hydrogel-based capacitive pressure sensor composed of two conductive layers and an intervening dielectric layer, forming an all-hydrogel sensing architecture. The conductive layers are fabricated from poly(3,4-ethylenedioxythiophene) (PEDOT) incorporated poly(ethylene glycol) diacrylate (PEGDA) hydrogels, while the dielectric layer consists of a pristine PEGDA matrix, enabling intimate interfacial bonding without the need for additional adhesives. The mechanical properties of the hydrogel system reveal tunable swelling behavior and elastic modulus as a function of PEGDA concentration. The resulting sensor displays a good sensitivity and additionally, the sensor exhibits stable electromechanical performance, featuring a short response time, allowing it to detect the pressure applied under repeated stimuli. Due to its flexible nature, the designed sensor demonstrates reliable detection of a wide range of mechanical stimuli, from small physiological signals to human motions. These findings highlight that the Janus hydrogel with integrated conductive and dielectric layers could be a promising platform for wearable health monitoring. Article link: https://advanced.onlinelibrary.wiley.com/doi/10.1002/advs.76893.