Polypyrrole-Coated Thermoplastic Polyurethane Nanofiber-Based Flexible Sensor for Biomarker Detection

The present work illustrates the potential of polypyrrole-coated (PPy) nanofiber-based flexible sensors for low-concentration (sub-ppm) ammonia detection. The sensor has been fabricated on synthesized novel flexible polyvinylpyrrolidone (PVP)/chitosan-based substrate using electrospinning of thermoplastic polyurethane (TPU) nanofibers, followed by spin coating of PPy. The elemental composition of the synthesized PPy has been confirmed by FTIR and XPS analysis and the surface morphology has been analyzed using FESEM. The response of the sensor toward ammonia at 100 ppb is observed to be 29.09%. Furthermore, the response and recovery times of the sensor at 100 ppb are 6 and 11 s, respectively, and it has shown appreciable selectivity toward ammonia as compared to other volatile organic compounds (VOCs). The fabricated sensor has shown an appreciable response under a relative humidity range of 40%RH to 80%RH. Moreover, the sensor has shown a stable response to the mechanical strain caused due to multiple bending cycles at different angles.