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 β‐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 µC 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 pm³ 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.

Polyvinylidene difluoride (PVDF) and its copolymers are promising electroactive polymers showing outstanding ferroelectric, piezoelectric, and pyroelectric properties in comparison with other organic materials. They have shown promise for applications in flexible sensors, energy-harvesting transducers, electronic skins, and flexible memories due to their biocompatibility, high chemical stability, bending and stretching abilities. PVDF can crystallize at five different phases of α, β, γ, δ, and ε; however, ferro-, piezo-, and pyroelectric properties of this polymer only originate from polar phases of β and γ. In this research, we reported fabrication of PVDF inkjet inks with enhanced β-phase crystallinity by incorporating barium titanate nanoparticles (BaTiO₃). BaTiO₃ not only acts as a nucleating agent to induce β-phase crystallinity, but it also improves the electric properties of PVDF through synergistic a ferroelectric polarization effect. PVDF-BaTiO₃ nanocomposite inkjet inks with different BaTiO₃ concentrations were prepared by wet ball milling coupled with bath ultrasonication. It was observed that the sample with 5 w% of BaTiO₃ had the highest β-phase crystallinity, while in higher ratios overall crystallinity deteriorated progressively, leading to more amorphous structures.

Printed electronics has opened up new insights towards fabrication of electronic components and devices. This manufacturing technique has been successfully employed as a complementary fabrication approach to conventional nanolithography and microfabrication processes to create flexible and stretchable electronics. Fluoropolymers are crucial components in electronic manufacturing, owing to their piezoelectric, triboelectric, pyroelectric, ferroelectric, and dielectric properties. In this research, we report fabrication of an inkjet-printed piezoelectric sensor based on poly(vinylidenefluoride trifluoroethylene) (PVDF-TrFE) and amine functionalized graphene oxide (AGO) for biomedical monitoring. The piezoelectric inkjet ink was obtained by optimizing the fluid mechanic properties based on Reynold and Weber numbers. The inkjet-printed freestanding film was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), wide-angle X-Ray scattering (WAXS), and differential scanning calorimetry (DSC). The piezoelectric sensor was fabricated out of the printed film by painting electrodes on each side, followed by wiring and encapsulation. The sensor was subjected to an electric field of 1500 kV/cm to align the internal dipoles and induce a net polarization. The obtained flexible piezoelectric sensor was employed for monitoring biomedical signals such as finger tapping, joint bending, and swallowing.

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, we propose a facile interfacial engineering approach based on amine-functionalized graphene oxide (AGO) to manipulate the intermolecular interactions in poly (vinylidenefluoride-trifluoroethylene) (PVDF-TrFE) to induce β-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 µC cm-2. PVDF-TrFE films with 0.1 wt% AGO demonstrated voltage coefficient, energy density, and energy-harvesting figure of merit values of 0.30 Vm N-1, 4.75 J cm-3, and 14 pm3 J-1, respectively, making it outstanding compared with state-of-the-art ceramic-free ferroelectric films. We believe this work can open-up new insights towards 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.