3D printed carbon nanotube/polyaniline/gelatin flexible NH3, stress, strain, temperature multifunctional sensor

The stability of 3D printed wearable flexible sensors is crucial for the practical application of hydrogel in wearable electronic devices and human-machine interfaces. However, conventional NH3 detectors have to face poor mechanical properties, and most hydrogel sensors have unstable humidity detection. Herein, we present a simple strategy to prepare in situ polymerized PANI conductive substances on CNTs. The PNI-CNTs were directly accessed in gelatin, and the thin-film sensors were used to 3D printed. The sensors enable monitoring NH3 detection over a wide range of 10–1200 ppm and stable humidity detection cycle. The hydrogel sensor shows excellent mechanical properties and keeps monitoring stress, strain temperature and human motion. In addition, the sensor shows high fatigue resistance after >2000 tensile cycles under fixed strain. The PANI-CNTs-gelatin sensor opens up a new horizon in human-computer interaction.