Different Scale Confinements of PVDF-TrFE as Functional Material of Piezoelectric Devices

In this paper, we report on the effect of micro- and nano-structuration on the piezoelectric properties of polymeric samples. We prepare micro-sized pillars and nano-wires (thus 1-D structures) of a piezoelectric polymer Poly(VinyliDene Fluoride-Tri FluoroEthylene) PVDF-TrFE and we compare their structural and piezoelectrical properties with a thin film (thus 2-D) of the same material. X-ray diffraction and infrared spectroscopy measurements show that the crystallization of the polymer into the ferroelectric β -phase is affected by the size of the confinement. The direct and converse piezoelectric characterization of the three polymeric structures shows important improvements as far as the nano-structuration is reached. As a proof of concept, we demonstrate the use of the three polymeric structures as potential flexible tactile sensors and bendable energy harvesters, showing a profound effect of the micro- and nano-structuration on the device performances.