Development of PVDF-HFP Based Flexible Hybrid Iontronic Film for Wearable Capacitive Sensor and E-Skin Applications

Recently, flexible pressure sensors in piezo-capacitive mechanisms have gained tremendous popularity due to their excellent potential for application in wearable sensors, electronic skin, human movement monitoring, etc. Herein, a high-performance piezo-capacitive composite containing poly(vinylidene fluoride-co-hexafluoropropylene)/graphene nanoribbon/([EMIM]Cl) (PVDF-HFP/GNR/IL) as an iontronic hybrid film is presented. The tandem use of GNR and IL in the matrix to prepare the iontronic hybrid yields a homogeneous film with a highly electroactive phase (81%) and improves mechanical properties. PVDF-HFP/GNR/IL is used as a dielectric layer to form an iontronic pressure sensor. The hybrid iontronic pressure sensor exhibits high sensitivity (approximate to 1.64 kPa(-1)) in the low-pressure range (<5 kPa) and a low detection limit of 1.29 Pa. Furthermore, it provides excellent performance with fast response (approximate to 98 ms) and high repeatability, reproducibility, and reliability (1000 cycles). The flexible hybrid sensor offers promising possibilities for its application in wearable technology by demonstrating good sensing performance in detecting body movements such as knee bending and physiological signals such as swallowing. This work provides a new perspective on the simplified design and integration of robust, multifunctional, flexible piezocapacitive sensors.