Paper Title
Wearable and Flexible Humidity Sensor Fabrication using Pad Printing Technique

Abstract - In this study, the flexible and wearable humidity sensor was fabricated with a pad printing machine using conductive silver and nickel inks. The humidity sensor was printed and exposed to the sintering process. Different print pass numbers and different sintering processes were applied to obtain stable conductivity on the surface of the samples with regard to the ink formulated for pad printing. In order to investigate the behavior of the printed humidity sensor against humidity, a humidity chamber was set up and the change in resistance of the sensor was measured with respect to change in the relative humidity of the chamber. It is found that by measuring the resistance of the sensor, the relative humidity of the environment where the sensor is located, can be estimated with the derived equation based on experimental results. It was observed that the sample with the best conductivity among the samples exposed to different sintering processes was the sample that had five printing passes and sintered at 150⁰C for 30 minutes. The printed humidity sensor is considered to be very effective for wearables where the humidity of the environment is critical. Keywords - Pad Printing, Humidity Sensor, Silver Conductive Ink, Nickel Conductive Ink, Wearable, Flexible