Polymeric Nanofibers with Ultrahigh Piezoelectricity via Self-Orientation of Nanocrystals

Abstract

Piezoelectricity in macromolecule polymers has been gaining immense attention, particularly for applications in biocompatible, implantable, and flexible electronic devices. This paper introduces core-shell-structured piezoelectric polyvinylidene fluoride (PVDF) nanofibers chemically wrapped by graphene oxide (GO) lamellae (PVDF/GO nanofibers), in which the polar β-phase nanocrystals are formed and uniaxially self-oriented by the synergistic effect of mechanical stretching, high-voltage alignment, and chemical interactions. The β-phase orientation of the PVDF/GO nanofibers along their axes is observed at atomic scale through high resolution transmission electron microscopy, and the β-phase content is found to be 88.5%. The piezoelectric properties of the PVDF/GO nanofibers are investigated in terms of piezoresponse mapping, local hysteresis loops, and polarization reversal by advanced piezoresponse force microscopy. The PVDF/GO nanofibers show a desirable out-of-plane piezoelectric constant (d) of -93.75 pm V (at 1.0 wt % GO addition), which is 426% higher than that of the conventional pure PVDF nanofibers. The mechanism behind this dramatic enhancement in piezoelectricity is elucidated by three-dimensional molecular modeling.

Durable, efficient, and flexible piezoelectric nanogenerator from electrospun PANi/HNT/PVDF blend nanocomposite

“…The piezoelectric coefficient (d 33 ) obtained for hybrid nanocomposite films was 30.6 pC/N, which is lesser than that of electrospun pure PNFs (30–57 pC/N). Large piezoelectric coefficients in electrospun PNFs are due to the improvement in electroactive phases, surface area, uniformity, and continuity of fibers .…”

Harvesting Energy from Human Activity: Ferroelectric Energy Harvesters for Portable, Implantable, and Biomedical Electronics

“…This strategy to prepare high β‐phase‐content PVDF for energy harvesting has also been reported by Wang et al. By wrapping the electrospinning PVDF with graphene oxide (GO), the piezoelectric response and energy harvesting performance can be further optimized as the GO reacts with the CF 2 groups of the molecular chains and further promote the PVDF to form the β phase (Figure e–g) . As a consequence, the energy‐harvesting device consisting of the PVDF/GO nanofibers produced about five times higher voltage output compared to that of the pristine PVDF nanofibers.…”

“Self‐Matched” Tribo/Piezoelectric Nanogenerators Using Vapor‐Induced Phase‐Separated Poly(vinylidene fluoride) and Recombinant Spider Silk

“…Then, the spin‐coated PET/PVDF was relocated to a humid environment for vapor‐induced phase‐separation processing (Figure S1, Supporting Information), during which PVDF chains would be polarized in the direction from the substrate to humid air as shown in the gray dashed line box of Figure b . Compared with electric‐field polarization, metal ion doping, and other reported methods, the vapor‐induced phase‐separation process is safer, more energy‐saving, and generates less pollution . In addition, the in situ polarization of PVDF on PET substrates provided robust adhesion, directly obtaining the triboelectric layer.…”