Direct Deposited Emulsion-Templated Composites for Monitoring of Fabric Strain

The need for developing stretchable, wearable, soft-strain sensors has risen in recent decades due to their relevance in various fields such as smart textiles, real-time monitoring, soft robotics, medical applications, and human motion detection. As is widely known, the creation of strain sensors encounters the difficulty of balancing different properties such as high sensitivity, adequate flexibility, good hysteresis and durability, and easy adaptability for incorporation into different surfaces. In this study, we are utilising liquid- exfoliated graphene nanosheets and commercially available silicones to develop the next generation of nanocomposite strain sensors. The graphene network is structured via emulsification to produce graphene-coated silicone droplets enabling high conductivity at relatively low graphene loadings. When combined with a highly elastic, flexible silicone matrix, this yields excellent electromechanical properties with a robust exponential response to applied strain. These emulsion-templated composites are robust to more than 500 cycles up to 100% strain and at a strain rate of 100%/s. The sensor exhibits good ohmic conduction, with an average conductivity of 0.8 ± 0.08 S/m. For the single, high strain rate (100%/s) strain to break measurement a well-defined (R²= 0.96) exponential response is observed up to 160% strain, featuring an extremely high relative resistance change over 2x10³ and a Gauge Factor of ~60. Moreover, these composites exhibit minimal hysteresis when deposited on a fabric substrate during cyclic strain, providing a system for monitoring high-performance fabrics.