Flexible ethanol sensors on glossy paper substrates operating at room temperature

Flexible sensors for the detection of ethanol at room temperature have been developed by depositing sensitive layers consisting of ITO nanopowder dispersed into poly-diallyldimethylammonium chloride (PDDAC), on the top of interdigitated electrodes based on conductive carbon nanotubes, previously printed onto flexible glossy paper substrates. The morphology and the microstructure of the interdigitated electrodes together with organic–inorganic sensing layer have been investigated by means of SEM, XRD and FT-IR. The electrical behaviour of the developed sensors at room temperature in response to low ethanol concentrations has been discussed as object of our research. The good ethanol sensing properties exhibited at room temperature by the composite film was supposed to originate from the electrostatic interaction occurring between the positively charged PDDAC polyelectrolyte and negatively charged ITO particles.