Design and development of textile-based strain sensors via screen printing

Textile-based strain sensors have recently attracted attention due to not only their flexibility and adaptability but also stretchability. Therefore, the main focus of this work is to develop highly flexible, highly stretchable and novel sensors based on several types of knitted fabrics and electrospun membranes with different kinds of inks. Sensors were fabricated by screen printing of different inks of NovaCentrix Metalon HPS-FLX21 and Creative Materials 127-48 (both silver-based) on two fabrics with different fabric structures and membranes obtained by electrospinning of thermoplastic polyurethane (TPU) as substrate. Readymade knitted substrates supplied by SIM-ART TEXTILE and electrospinning of dissolved TPU pellets in Dimethylformamide (DMF) and Ethyl acetate (EA) mixture provided a fibrous substrate to be utilized in manufacturing of the sensors. The patterns predetermined were transferred onto these substrates by screen printing method using silver based conductive inks in order to ensure sufficient conductivity. For all of these sensors, optimum processing conditions have been determined within the scope of the experiments. As a result, the as-printed substrates have been oven-cured to finalize the fabrication process of the sensors. According to the findings of the study, Creative Materials ink was found to display quite good performance on both TPU membrane and knitted fabric-based strain sensors whereas NovaCentrix ink did not perform as well. Developed sensors in this study can be potentially used in wearable electronics for human motion monitoring applications.