2D Nanomaterials Incorporated Poly(vinylidene fluoride) Nanocomposites: Morphology, Crystalline Structure, and Dielectric, Ferroelectric, and Piezoelectric Properties

Abstract

Two-dimensional layered nanomaterials (hexagonal boron nitride (h-BN) and expanded graphite (EG)) incorporated poly(vinylidene fluoride) (PVDF) nanocomposites were fabricated via high-shear solution mixing accompanied by compression molding. “Ultrasonication” followed by “centrifugation” was employed to “de-stack” h-BN and EG, which exhibited a decrease in “agglomerate” size in PVDF/h-BN and PVDF/EG nanocomposites. Further, the PVDF/h-BN nanocomposite showed a polar fraction of ∼57% at 0.50 wt % of h-BN concentration with an increased β-phase content, whereas the PVDF/EG nanocomposite showed a higher content of γ-phase as compared to β-phase. Moreover, dielectric investigations indicated that the “ultrasonicated” and “centrifuged” h-BN- and EG-based PVDF nanocomposites exhibit the highest dielectric properties owing to improved interfacial and dipolar polarizations. The piezoelectric strain coefficient of PVDF/0.16BN and PVDF/0.17EG nanocomposites exhibited d 33 values of ∼99 and ∼91 pm/V, respectively. Finally, sensor devices were fabricated based on PVDF/EG and PVDF/h-BN nanocomposite films, which showed a maximum peak-to-peak voltage of ∼24 V (at 0.17 wt % EG) and ∼14 V (at 0.16 wt % h-BN), respectively. A systematic investigation was carried out to relate the influence of finely dispersed h-BN and EG on the interfacial interactions, polar phase formation, and the piezoelectric property of PVDF/h-BN and PVDF/EG nanocomposites.

Augmenting Piezoelectric Performance of Poly (vinylidene fluoride) Nanogenerator with Zinc Oxide Nanorods Decorated Reduced Graphene Oxide Nanosheets

“…The FTIR absorption bands of N-PVDF, PVDF/rGO, and PVDF/ZnO nanocomposites are shown in Figure S3a,b within the wavenumber range of 1600–600 cm –1 . The detected absorption bands at 613 and 764 cm –1 , which are linked to −CF 2 bending and skeletal bending respectively, along with the absorption band at 796 cm –1 , associated with −CH 2 rocking, are believed to be characteristic of the nonpolar α phase of PVDF. The observed band at 840 cm –1 indicates the presence of the polar β and γ phases, as it involves CH 2 stretching, CF 2 stretching, and skeletal C–C stretching. , Furthermore, the absorption band at 812 cm –1 corresponds to the γ-phase–CH 2 out-of-plane wagging, while the absorption bands at 1234 and 1275 cm –1 are indicative of C–F out-of-plane deformations in the γ-phase and β-phase, , respectively.…”

“…This is because the ferroelectric domains adjust their orientation when an electric field is applied, resulting in the emergence of ferroelectric characteristics in the nanocomposites . In general, nanocomposites that possess a greater polar phase and enhanced interfacial interactions (refer to Section S7 and Table S2) are likely to demonstrate favorable piezoelectric characteristics …”

Nickel-Oxide-Doped Polyvinylidene Fluoride Nanofiber-Based Flexible Triboelectric Nanogenerator for Energy Harvesting and Healthcare Monitoring Applications

“…The net dipole moment exhibited by the β-phase is 8 × 10 –30 C·m per unit cell. Moreover, the β-phase of PVDF plays the most pivotal role in enhancing the electrical output of the fabricated TENGs. , Currently, the betterment of PVDF dielectric characteristics and most electroactive β-phase have been explored by incorporating or doping different nanofillers such as Ag NWsx, CuO NPs, NiO NPs, , BaTiO 3 , graphene oxide, and sepiolite (an inorganic nanoclay) . Out of these, NiO NPs are the most significant nanofillers to dope into the PVDF matrix because they have the ability to modify the mechanical, electrical (band gap 3.6–4 eV), and magnetic properties without affecting the flexibility of the nanofiber mats. , Numerous methods have been published in the literature for NiO NP synthesis, including ultrasonication, sol–gel, coprecipitation, and microwave pyrolysis.…”

Improved Breakdown Strength and Restrained Leakage Current of Sandwich Structure Ferroelectric Polymers Utilizing Ultra-Thin Al2O3 Nanosheets

“…However, ferroelectric polymers' C-F bonds have strong orientation polarization, which causes low breakdown strength in polymers [12]. To improve the breakdown strength, energy storage efficiency, dielectric permittivity, and capacitive energy density, polar polymers are extensively investigated with organic blends [13,14], multilayer design [15,16] or inorganic fillers of different dimensions [2,[17][18][19], such as nanoparticles and quantum dots (0D) [20][21][22][23][24][25], nanofibers, nanorod array (one-dimensional, 1D) [26][27][28][29], as well as nanoplates and nanosheets (two-dimensional, 2D) [30][31][32][33][34].…”

“…Two-dimensional nanosheets such as Boron Nitride (BN), clay, TiO 2 , NaNbO 3 , and ZrO 2 et al [30][31][32][33][34] are usually used in nanocomposites to improve the dielectric properties and storage density. Alumina can also be used to regulate the dielectric properties of materials [36].…”