P(VDF-TrFE)/PVP/ionic liquid-based piezo-ionic polymer blend for touch sensing applications

Ionic polymers (IPs) have been in high demand for application in piezoresistive sensors, ionic skins, humidity sensors, and wearable sensors owing to their high flexibility, hydrophilicity, and ionic conductivity. However, IP sensors produced low-power densities (nW/cm2 ∼ µW /cm2) even at high applied pressures (40–100 MPa), which are insufficient for practical applications such as portable chargers. Here, a piezo-ionic polymer blend (PIPB) sensor is developed using poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE)/ polyvinylpyrrolidone (PVP)/1-butyl-3-methylimidazolium-hydrogen sulfate (acidic ionic liquid, AIL) blend ratio of 30/15/55 with microrods (diameter of 0.2–0.7 µm) and pores (diameter of 1.2–4 µm) structure that generates an output voltage of 24 V and current density of 2.35 A/cm2, resulting in a high power density of 3 W/cm2 with an applied pressure of 200 Pa. The PIPB sensor also generates an output voltage of 6.5 V with a finger-tapping pressure of 47 Pa, which was utilized to power LEDs. With notable features of high tensile strain % of 3471 of the PIPB sensor, it detects pulses and a finger movement of 0–180º from a human body, generating output voltages of 1 and 8 V. The present study demonstrates the PIPB sensor’s potential application in energy-harvesting and wearable devices requiring high power densities.