Heart rate monitoring system based on piezoelectric poly(vinylidene fluoride-co-trifluoroethylene) composites with barium strontium titanate ceramic particles

Abstract

A heart rate sensor device has been designed and developed based on a composite material based on poly(vinylidene fluoride – co – trifluoroethylene), P(VDF-TrFE) as polymer matrix and barium strontium titanate (BST) particles as ceramic fillers. The composite films were prepared by solvent casting varying the ceramic particles content between up to 40 wt%, allowing to tailor the dielectric and piezoelectric response. The morphology, polymer phase and thermal properties are independent of the ceramic filler content, whereas the dielectric constant increases significantly with increasing filler content, the largest dielectric constant, ε’ = 38 at 1 kHz, being obtained for the composite with 40 wt% of ceramic particles. Further, the highest piezoelectric response, also dependent on ceramic filler content, is |d33|= 29 pC/N, being obtained for the 10 wt% ceramic particle content film. It is also shown by piezoresponse force microscopy that higher ceramic particles are characterized by more stable ferroelectric domains. The composite has been successfully proved for its potential in heart rate monitoring applications, exhibiting high levels of precision as well as reliability. This work on heart rate sensing presents a material suitable for its incorporation into wearable gadgets, medical devices, and sports equipment, compatible with integration by printing technologies, enabling consumers to access immediate data relevant to their cardiovascular health.