Interfacial Engineering of PVDF-TrFE toward Higher Piezoelectric, Ferroelectric, and Dielectric Performance for Sensing and Energy Harvesting Applications

The electrical properties of pristine fluoropolymers are inferior due to their low polar crystalline phase content and rigid dipoles that tend to retain their fixed moment and orientation. Several strategies, such as electrospinning, electrohydrodynamic pulling, and template-assisted growing, have been proven to enhance the electrical properties of fluoropolymers; however, these techniques are mostly very hard to scale-up and expensive. Here, a facile interfacial engineering approach based on amine-functionalized graphene oxide (AGO) is proposed to manipulate the intermolecular interactions in poly(vinylidenefluoride-trifluoroethylene) (PVDF-TrFE) to induce beta-phase formation, enlarge the lamellae dimensions, and align the micro-dipoles. The coexistence of primary amine and hydroxyl groups on AGO nanosheets offers strong hydrogen bonding with fluorine atoms, which facilitates domain alignment, resulting in an exceptional remnant polarization of 11.3 mu C cm(-2). PVDF-TrFE films with 0.1 wt.% AGO demonstrate voltage coefficient, energy density, and energy-harvesting figure of merit values of 0.30 Vm N-1, 4.75 J cm(-3), and 14 pm(3) J(-1), respectively, making it outstanding compared with state-of-the-art ceramic-free ferroelectric films. It is believed that this work can open-up new insights toward structural and morphological tailoring of fluoropolymers to enhance their electrical and electromechanical performance and pave the way for their industrial deployment in next-generation wearables and human-machine interfaces.

Automated summary

An interfacial engineering approach using amine-functionalized graphene oxide (AGO) is proposed to enhance the electrical properties of fluoropolymers. This method enables the formation of beta-phase, enlargement of lamellae dimensions, and alignment of micro-dipoles. The resulting PVDF-TrFE films with AGO demonstrate exceptional remnant polarization and high voltage coefficient, energy density, and energy-harvesting figure of merit values, making them suitable for next-generation wearables and human-machine interfaces.