Manufacturing and characterization of novel silicone/natural fabric/graphene‐based functional composites for human body motion sensing

This study focuses on the development of strain‐sensors utilizing biodegradable natural fabrics (cotton, flax, and wool) and graphene nanoplatelets (GN) through novel coating techniques. A systematic study on improving the electrical conductivity of natural fiber fabrics to be used as effecting sensing stimuli was conducted by varying the proportions of graphene. To further enhance the conductivity, GN was hybridized with conducting polymers, such as polypyrrole (PPy), polyaniline (PANI), and with carbon black (CB). The electrical conductivity, morphological, and mechanical characterizations were carried composites for detailed comparative analysis. The conductive composites were incorporated into flexible and stretchable silicone elastomer (Ecoflex) to be used as strain sensors. Electromechanical characterizations were carried out on the composite sensors and their performance on different human body motions, including finger, wrist, elbow, and knee movements were assessed. The results showed that the addition of hybrids, such as PPy increased the electrical conductivity in fabrics (for instance, cotton with a conductivity of 1.7 S.cm−1). However, the addition of PANI tends to have a negative effect on the conductivity due to poor ability to deposit on the fiber surface. It was observed that the thermal stability was improved with the addition of conductive particles which gives rise to excellent sensitivity and durability of the composite sensors.