Advanced fabrication of wearable piezoresistive sensors for smart textile applications

The rapid growth in wearable electronics textiles has promoted the development of flexible sensors. However, most recent efforts in fabricating textile-based sensors focus on a single approach of improving the sensor’s performance and covering only a small area. There are a number of factors to be considered for a sensor to qualify as a wearable sensor, including its fabrication, sensing capabilities and, most importantly, its ability to be worn without discomfort. Hence, this study aimed to design and develop wearable piezoresistive sensors with conductive textiles using a novel technique, “stitching”. This is considered the most scalable fabrication technique and allows the creation of free-form sensor designs. The objectives include optimising the fabrication method by varying the sensor construction parameters (stitch density, number of twists and linear density of the thread etc.) to achieve diverse sensor performance and specifications. Moreover, the design of the stitched sensor is improved by reducing the stack layers, thus, enhancing the electromechanical performance and skin-sensor interface. The sensors were extensively characterised to evaluate their performances and then embedded onto garments to monitor human muscle activities in real-time. This research shows an innovative method to fabricate textile-based piezoresistive sensors for wearable applications. Sensors developed through stitching are lightweight and flexible, and by varying the parameters, they demonstrate different working ranges and sensitivities, which can be used for various potential applications in fashion, sports, and healthcare. This research suggests the future direction of e-textiles; wearable pressure sensors in terms of new design, fabrication, evaluation, and embedding techniques.