NBR and TPU Elastomer-Based Reduced Graphene Oxide Nanocomposites for Sensing Applications

The phenomenal electronic properties of carbon nanomaterials, especially reduced graphene oxide (RGO), have enabled their use in composite and pure forms for manifold industrial applications, including flexible and wearable electronics, soft robotics, strain and pressure sensors, and energy storage devices such as stretchable supercapacitors. RGO has been given priority over other allotropes of graphene for developing flexible sensors due to its affinity toward water and various organic polar solvents, as well as its simple fabrication processes. This review highlights the most significant research on RGO-based elastomer composites, particularly for strain-sensing applications. The polymers examined in this review are nitrile rubber (NBR) and thermoplastic polyurethane (TPU). NBR and TPU have been widely used in the fabrication of wearable sensors due to their inherent mechanical strength. The above-specified polymers have been used either as pure substrates or as base polymers to mix with RGO at optimized ratios, as well as in other hybrid nanomaterials. The current challenges and optimal conditions for RGO-based polymer (NBR and TPU) composites are discussed in detail at the end of this article.