Highly sensitive, flexible and wearable piezoelectric motion sensor based on PT promoted β-phase PVDF

Wearable electronic devices with biocompatibility and stability to monitor the practical human physiological states are urgently expected for some intensive disease recovery or healthy fitness improvement. In this work, a highly sensitive piezoelectric sensor with the aid of polythiophene (PT) promoting polyvinylidene Fluoride (PVDF) from α-phase to β-phase was designed. Electric-sensitivity of 4.961 V/N is obtained at the low-pressure and 0.09 N periodic pressure positively produces considerable output open circuit voltage. It is proved that PT facilitates PVDF to accumulate charge carriers at their interfaces, resulting in interface polarization and thus extremely piezoelectric sensitivity. Reliability test suggested the sensor stays stable performance after a long-term (~2.6% decline after 5000 cycles) repetitive deformation. Through the practices of our assembled wearable sensor demonstrating its powerful ability in recording human joint movement and breathing, which also shows that it is very promising in online movement monitoring of personal health.