Inkjet Printed Ag Nanomaterials based Strain Sensors for Wearable Sensing Applications

Abstract

Of late, the demand of wearable sensors has exponentially risen. For example, strain sensors that can be worn and are skin mountable play a significant role in the areas of human motion detection, healthcare, soft robotics, electronic skin, and sport as well as fitness tracking. It is known that traditional strain sensing devices made of semiconductors and metals exhibit low sensitivities (GFlt 2), low strain sensing range (lt 5%) and exhibit rigidity which are undesirable characteristics for wearable sensing applications. In order to address these issues, metal nanomaterials such as AgNWs-AgNPs nanohybrids are now employed as active and functional sensing devices for the fabrication of wearable strain sensors. Further, inkjet printing process has been utilized for fabricating wearable devices (together with advantages of wide sensing range and high sensitivity) due to its cost effectiveness and capability of large scale production. The stretchable, wearable, and skin-mountable strain sensors have garnered significant research attention in consumer and medical products which may be attributable to various aspects like cost-effectiveness and ergonomics fuelled by the development in miniaturized electronics, growing consumer awareness for health related issues, and constant need for medical practitioners to obtain quality medical data from patients. Recently, the fabrication of strain sensors with high sensitivity and high stretchability, which can precisely monitor subtle strains and large mechanical deformations exhibited by the human bodily motions, is critical for healthcare, human-machine interfaces, and biomedical electronics. However, a significant challenge still exists i.e. achieving strain sensors with high sensitivity, high linearity, and high stretchability by a facile, low-cost and scalable fabrication technique. Herein, in this research, we achieve AgNWs-AgNPs/Ecoflex based composite strain sensors via inkjet printing technique which precisely deposits functional materials in a rapid...