A Decoupled Flexible Temperature‐Strain Dual Function Sensor for Extracorporeal Circulatory System Monitoring

ABSTRACT Temperature and strain monitoring in extracorporeal circulatory systems is vital for maintaining physiological homeostasis. Flexible integrated temperature‐strain sensors overcome single‐function device limitations but suffer from signal crosstalk—thermal expansion‐induced deformation of the temperature unit and Joule heat from the strain unit's resistance. Herein, we developed a decoupled dual‐function sensor with a three‐layer architecture: a graphene /poly (3,4‐ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) temperature‐sensing layer, a thermoplastic polyurethane (TPU) nanofiber thermal insulation layer, and a silver/graphene/PEDOT:PSS strain‐responsive layer. Benefiting from the porous structure of the graphene composite conductive hydrogel, which ensures stable thermoelectric performance under strains, the insulating TPU nanofiber that mitigates heat transfer to the strain‐sensing component, and the layered architecture that facilitates mechanical interconnection and independent electrical output of the two sensing units, the sensor achieves spatial independent decoupling and effectively suppresses signal crosstalk between parameters and across spatial domains. Temperature is detected via thermoelectric voltage from changes in carrier concentration, while strain is measured via resistance variations from layer cracks. The sensor exhibits a Seebeck coefficient of 0.002 V/°C and a strain gauge factor of 3.13 × 10 5 . Validation in a simulated artificial heart circulatory system confirmed high‐accuracy real‐time monitoring of temperature and strain, demonstrating great potential in clinical physiological monitoring.