Printing sensor on flexible substrates for detection of volatile organic compounds

This paper investigates printing functional materials on diverse flexible substrates for rapid detection of volatile organic compounds (VOCs). Inkjet printing and doctor blade coating is performed for rapid manufacturing of the sensing devices. The three different substrates selected are polyethylene terephthalate (PET), cotton fabric and a common A4 type printing paper. The structural and morphological properties of the substrates are exploited to compare the detection of three different types of VOCs, such as acetone, ethanol and isopropanol. A silver (Ag) nanoparticles-based ink at suitable properties for inkjet printer is used for developing the interdigital electrodes. A nanocomposite of Carbon-based paste is applied as sensing layer. Geometrical parameters of the devices, materials, processing and sintering conditions are kept similar, to only explore the distinguished sensing capabilities based on the substrate materials. Two different concentrations i.e. 4 and 22 ppm (parts per million) of the representative VOCs are applied in the test chamber and corresponding chemoresistance values are recorded using a sourcemeter. The different resistance peak values and responses times are correlated with the type of substrates and a comparative study is performed based on the type of substrate. This research presents greater contribution in the field of large area, cost-effective and wearable VOCs sensors that are highly demanding both for industrial as well as environmental monitoring. Some of these VOCs are considered as potential bioanalytes, which can be used in the recognition of several chronic diseases using these wearable sensing devices.