The purpose of master's thesis “Printed chemical sensors” is preparation of screen printed chemical sensors. Printing forms for multi-layered prints of interdigitated capacitors were prepared and improved on the basis of measurement results. The feasibility of seven print substrates based on polymer materials was analysed. Suitable substrates were chosen for further study and optimal drying parameters were specified after thorough testing of materials’ dimensional stability at high temperatures and results of differential scanning calorimetry were obtained. Commercially available printing inks were applied, including one silver-based conductive ink and two dielectric inks. Conductive structures with resolution of up to 300 microns were printed with a screen density of 120 lines/cm. Two-layered elements of dielectric printing ink and an additional layer of conductive ink were successfully applied onto a printing substrate coated with a conductive indium tin oxide layer. Capacitance of a parallel-plate and interdigitated capacitor was determined by the help of position of electrodes. The results confirm that the change of UV energy applied for curing of the dielectric ink has no significant influence on the capacitance of printed sensors, but is a factor of capacitor function and surface area. Capacitance was greater when measured as a parallel-plate capacitor with dielectric layer between two electrodes and larger surface area than interdigitated capacitor printed on the same sample. Factor of dissipation diminishes with higher UV energy applied for curing of the dielectric ink. Sensor response to changes in relative humidity is even and can be reproduced. Change of capacity of sensor is higher with increase in relative humidity, thus the prepared sensors are properly responsive.
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