Flexible strain sensing filaments based on styrene-butadiene-styrene co-polymer mixed with carbon particle filled thermoplastic polyurethane

In this work, nanocomposite filament-based sensors made from polystyrene-block-polybutadiene-block-polystyrene (SBS) and graphene-based electrically conductive thermoplastic polyurethane (C-TPU) have been fabricated using a small extrusion process. Because of the high flexibility of the polymer matrix selected and the processing method employed, it is possible to reach elongations above 150% with an adjustable length and diameter making them good candidates for applications where flexible and adaptable sensors are needed. The electrical response of the filaments is measured at different elongations exhibiting good reproducibility and linearity. Strain gauge factors up to 26 were obtained showing up higher sensitivity than commercial metallic strain gauges. This kind of sensors can be applied in many fields including wearable electronics and structural health monitoring.