Polyelectrolyte based ionic polymer sensor for piezoresistive and wearable signals

Achieving high sensitivity, flexibility, reliability, and repeatability are crucial for the advancement of ionic polymer sensors. The biocompatibility and desired conducting behavior of polyvinyl alcohol (PVA)-based ionic polymer sensors (IPS) make them ideal for piezoresistive and wearable applications. This study presents the development of IPS using various compositions of PVA/polyvinyl sulphonic acid (PVSA) sodium salt blend for dielectric, piezoresistive, and wearable applications. Among these, the 70/30 blend exhibited large pores, enhancing tensile strain % up to 611 and water uptake (WUP) up to 1.7, resulting in a high gauge factor (G) of 294—the highest among existing PVA–based IPS. This blend also demonstrated a 162-fold higher G and a 331-fold higher sensitivity (ΔR/R) compared to pure PVA. The exceptional ductility of the 70/30-based IPS enables it to detect breathing and finger-bending signals when attached to the human body. In contrast, the 50/50-based IPS exhibited the highest dielectric constant (1053) and the lowest value of loss factor (2.6), indicating its suitability for storage device applications. The PVSA/PVA IPS achieved DC conductivity in the range of 6 × 10⁻⁶ S/cm to 18 × 10⁻⁶ S/cm, confirming their applicability in piezoresistive and wearable sensing applications. These findings demonstrate that PVA/PVSA-based IPS offers a versatile and cost-effective solution for next-generation flexible and wearable sensors.