Electrospinning/electrospray of polyvinylidene fluoride (PVDF): piezoelectric nanofibers

Polyvinylidene fluoride (PVDF) is one of the most studied polymer systems that exhibits piezoelectric, pyroelectric, and ferroelectric properties. It is well known that PVDF is able to crystallize in four different forms that involve three different chain conformations, namely alpha, beta, gamma, and delta phases. Among the four polymorphs, the beta-phase has the largest spontaneous polarization per unit cell and thus exhibits the highest electro active properties. In the past few decades, many researches have been done to increase the beta-phase content in PVDF using various processing techniques and additives. One of these processing methods is electrospinning/ electrospray with organic/inorganic additives, nanoparticles or carbon nanotubes. Material and structural analyses on fabricated nanofibers using instruments such as X-ray diffraction, Fourier transform infrared, Differential Scanning Calorimetry, and Scanning Electron Microscope as the characterizations of piezoelectric nanofibers are carried out. This article attempts to have an overview on the electrospinning process of PVDF as a piezoelectric polymer, method of characterization of its beta-phase and its application as a nanogenerator.