Double-network conductive hydrogel for non-contact respiratory monitoring

Severe disruptions in the respiratory system can lead to a range of health issues. Real-time monitoring of respiration is crucial for preventing and treating associated diseases. Herein, a simple and portable respiratory monitoring device was developed by simply integrating the conductive hydrogel on the medical mask. The core conductive hydrogel was successfully synthesized by interpenetrating carboxymethyl cellulose into a HA network through a ‘one-pot’ thermal-initiated polymerization process. This hydrogel exhibits superior comprehensive performance, including high tensile strain (1100 %), high gauge factor (2.45), a wide strain detection range (0.1–1000 %), and strong adhesion (40 kPa). When subjected to external force, the structure of the hydrogel changes, resulting in alterations to its internal conductive pathways, which subsequently affect the resistance. The integrated device shows high sensitivity, moisture resistance and cycle stability for monitoring significant human physical movements. Especially, he integrated device can effectively recognize the breathing behaviors associated with obstructive sleep apnea diseases including cough, apnea, and snoring, as well as achieving hour-level continuous service more than 1000 cycles. These exceptional characteristics indicate that these novel hydrogels hold great potential in applications such as smart wearable electronics, intelligent respiratory monitoring and diagnosis.