Inkjet‐Printed Composites for Room‐Temperature VOC Sensing: From Ink Formulation to Sensor Characterization

The authors report the fabrication and characterization of chemiresistive sensors, composed of a thermoplastic elastomer (TPE), styrene‐ethylene‐ran‐butylene‐styrene, and a high‐structure carbon black (CB) targeted for detecting hydrocarbons at or near room‐temperature (RT). The sensors are fabricated via drop‐on‐demand inkjet‐printing (IJP) for which jettable inks are formulated and their printability systematically studied as a function of different ink components, that is, polymer concentration, solvent mixture, and CB dispersion. The printed sensors are characterized upon exposure to various analytes showing a high sensitivity to nonpolar compounds (pentane, heptane), moderate sensitivity to polar aprotic analytes (acetone), low sensitivity to polar protic analytes (ethanol), and almost no sensitivity to humidity. While operating at 28 °C, the sensors have a fast response and recovery (a few seconds) owing to the rapid analyte diffusion into the TPE. Moreover, it is shown that the sensor response and recovery further improve without affecting the sensitivity by increasing the droplet spacing in the printed film. Such performance demonstrates the great potential of TPE‐based nanocomposites for RT detection of volatile organic compounds and IJP as a suitable manufacturing method for integrating the sensing material with the electronic devices in applications where low‐cost sensors with low power consumption are required.