Polyurethane Packed Graphene-Coated Spider Silk by Dip-Casting for Highly Stretchable Strain Sensor

Abstract

In recent years, naturally occurring materials are getting tremendous attention infabrication of future wearable electronic devices. Among these materials, spider silk is well-known for its outstandingmechanical strength and physical properties. Keeping in view the same, a highly stretchable strain sensor has been fabricatedin this work based on polyurethane packed graphene coated spider silkusingsimple dip-casting method. The proposed sensor shows a high mechanical strength, excellent sensitivity towards strain, and impressiverecovering properties due to the self-healing abilities of the polyurethane packaging.Polyurethane also protectsthe sensor from external environmental parameters and acts as an encapsulation to improve the lifetime of the device.The fabricated devices maintain theirperformanceparameters and other properties upto 40 % stretchability. FE-SEM and EDS elemental mapping was used to verify the morphological properties and the homogenous coating of graphene on the spider silk fiber. The sensors were then attached to different parts of human body to detect the pulse-rate, angle, and postureof different joints showing outstanding results. This work could open a new opportunity towards the design and fabrication of future wearable sensors using naturally occurring materials and theirapplied electronic applications.