am0c02578_si_001.pdf (1.01 MB)
Enhanced Piezoelectricity of Electrospun Polyvinylidene Fluoride Fibers for Energy Harvesting
journal contribution
posted on 2020-03-04, 18:40 authored by Piotr K. Szewczyk, Arkadiusz Gradys, Sung Kyun Kim, Luana Persano, Mateusz Marzec, Aleksandr Kryshtal, Tommaso Busolo, Alessandra Toncelli, Dario Pisignano, Andrzej Bernasik, Sohini Kar-Narayan, Paweł Sajkiewicz, Urszula StachewiczPiezoelectric
polymers are promising energy materials for wearable and implantable
applications for replacing bulky batteries in small and flexible electronics.
Therefore, many research studies are focused on understanding the
behavior of polymers at a molecular level and designing new polymer-based
generators using polyvinylidene fluoride (PVDF). In this work, we
investigated the influence of voltage polarity and ambient relative
humidity in electrospinning of PVDF for energy-harvesting applications.
A multitechnique approach combining microscopy and spectroscopy was
used to study the content of the β-phase and piezoelectric properties
of PVDF fibers. We shed new light on β-phase crystallization
in electrospun PVDF and showed the enhanced piezoelectric response
of the PVDF fiber-based generator produced with the negative voltage
polarity at a relative humidity of 60%. Above all, we proved that
not only crystallinity but also surface chemistry is crucial for improving
piezoelectric performance in PVDF fibers. Controlling relative humidity
and voltage polarity increased the d33 piezoelectric coefficient
for PVDF fibers by more than three times and allowed us to generate
a power density of 0.6 μW·cm–2 from PVDF
membranes. This study showed that the electrospinning technique can
be used as a single-step process for obtaining a vast spectrum of
PVDF fibers exhibiting different physicochemical properties with β-phase
crystallinity reaching up to 74%. The humidity and voltage polarity
are critical factors in respect of chemistry of the material on piezoelectricity
of PVDF fibers, which establishes a novel route to engineer materials
for energy-harvesting and sensing applications.