Cobalt ferrite-embedded polyvinylidene fluoride electrospun nanocomposites as flexible triboelectric sensors for healthcare and polysomnographic monitoring applications

Human respiration is a vital physiological function of the body and a key metric for assessing overall health, particularly in conditions related to sleep deprivation. However, developing a real-time system for detecting sleeping position, heartbeat, and respiration is challenging yet crucial. Such a system should be easy to fabricate, comfortable to wear, and highly sensitive. In this study, we fabricated a flexible electrospun cobalt ferrite (CoFe₂O₄, CF) embedded polyvinylidene fluoride (PVDF) nanocomposite (NC) using an electrospinning technique. Additionally, we investigated the influence of varying CF content (0, 1, 3, and 5 wt%) on the crystalline β-phase in PVDF. The triboelectric nanogenerator (TENG) device was fabricated using PVDF-CF (P-CF) NC as the tribo-negative layer and non-woven fabric of thermoplastic polyurethane (TPU) as the tribo-positive layer. Among the four sample combinations used in this study, P-CF-3 (3 wt% CF in PVDF)/TPU TENG exhibited a significantly higher triboelectric open circuit voltage (V_oc) of 5.8 V, nearly three times higher as compared to P-CF-0/TPU TENG (1.7 V). This work demonstrates an efficient method for enhancing the output efficacy of flexible TENG devices by varying the nanofiller concentration. Moreover, the fabricated TENG device was efficiently tested for real-time healthcare monitoring (HCM) and polysomnographic (PSG) related studies. This study aspires to provide a novel and pragmatic way of identifying real-time sleeping disorders and respiratory monitoring.