Atomistic modelling of processes involved in poling of PVDF

Abstract

Poling processes play an important role in the design and preparation of many ferroelectric materials for practical uses in the field of sensors and actuators. Particularly, the processing of piezoelectric β-poly(vinylidene fluoride) (β-PVDF) involves mechanical stretching in order to transform the extruded α-phase into the β-phase and poling of this later material in order to optimise the piezoelectric response. This poling process affects the orientation of the dipolar moments of the β-chains and improves the α to β transformation.Poling processes in general and in PVDF in particular are still quite empirical because a firm understanding of the physical processes involved in poling has not been fully established.In the present work we use a self-consistent quantum molecular dynamics method to study the effect of the electric field on both α and β chains of PVDF. The orientation of the dipolar moments in each chain as a function of an electric field and the accompanying structural modifications due to these reorientations will be the main parameters discussed.The theoretical results will be used to better understand the changes at a molecular level due to the poling process, as observed in FTIR experiments, performed in poled and non-poled β-PVDF from the same batch.

Side-selective self-assembly of graphene and FLG on piezoelectric PVDF from suspension

“…This arrangement of chains creates a permanent dipole in the poled PVDF film giving the material piezoelectric properties. Using FT-IR absorbance spectroscopy, the proportions of beta phase in the commercial substrates used were determined to be 34% for the non-poled PVDF, and 86-88% for the poled material, with very small differences between the "+ve" and the "-ve" faces, well in accordance with the literature [25,26].…”

An Energy-Harvesting Device Based on Mechano-Electrospun Aligned Poly(vinylidene fluoride) Fiber Arrays

“…To determine the fraction of the content of the β phase at different velocities, infrared spectroscopy absorption bands at 795 and 840 cm −1 are characterized as the α and β phases, respectively. The relative fraction of the β phase, F(β), can be calculated using the following equation: (17) …”

Yeşil Enerji Tekstil Uygulamaları İçin Piezoelektrik Monofilament Eldesi

“…Thermal, mechanical and electrical conditions were applied during the filament production process on a customised melt extruder used in Piezoelectricity is one of the possible green electricity generation methods since piezoelectric materials can generate an electric charge when an external stress is applied "direct piezoelectric effect" (Figure 1(a)) and conversely these materials undergo a shape change when an external voltage is applied "converse piezoelectric effect" (Figure 1(b)). Since the discovery of piezoelectricity in ceramics and polymers, various studies have been carried out on structural changes [1][2][3], poling [4][5][6][7][8][9] and energy harvesting applications [10][11][12][13]. Materials that have direct piezoelectric property are mostly used for energy harvesting which describes the process of extracting energy from the environment then converting and storing it in the form of electrical energy.…”