Effect of Poling on β -Phase Structure of Electrospun PVDF-TrFE Nanofiber Film

This article elucidates the field-assisted high-temperature poling effect on the improvement of crystallinity of β -phase structure of the electrospun-deposited PVDF-TrFE nanofiber film. Morphology, crystallinity and their variation/behavior on poling ferroelectric polymer electrospun PVDF-TrFE nanofibers have been investigated thoroughly using FESEM, XRD and Raman spectroscopy. Field-assisted high-temperature poling at 120 °C of PVDF-TrFE nanofiber film generated a condition similar to high mechanical stress which assisted the nucleation and growth kinetics of new β crystals and their reorientation mechanism due to sliding diffusion of ferroelectric polymer chains along the chain axis in the nanofiber. On increasing the poling time duration number of oriented polar crystalline domain regions in deposited nanofiber films rises which resulted in enhancement of crystallinity of films. XRD and Raman analysis complemented the study of enhancement of β -phase crystallinity in as-deposited PVDF-TrFE nanofiber film on poling with no noticeable change in the dimension and morphology of the nanofibers. Further, enhancement of ferroelectric property of the poled nanofiber film has been observed with increase of poling time which supports our interpretation of poling facilitated nucleation and growth kinetics of new β -crystal with long trans-sequences in deposited nanofiber films.