Influence of Ferroelectric Filler Size and Clustering on the Electrical Properties of (Ag–BaTiO₃)–PVDF Sub-Percolative Hybrid Composites

Abstract

The paper presents a study concerning the role of ferroelectric filler size and clustering in the dielectric properties of 20%BaTiO 3 −80%PVDF and of 20% (2%Ag−98%BaTiO 3 )−PVDF hybrid nanocomposites. By finite element calculations, it was shown that using fillers with ε > 10 3 does not provide a permittivity rise in the composites and the effective dielectric constant tends to saturate to specific values determined by the filler size and agglomeration degree. Irrespective of the ferroelectric filler sizes, the addition of metallic ultrafine nanoparticles (Ag) results in permittivity intensification and the effect is even stronger if the metallic nanoparticles are connected to a higher degree with the ferroelectric particles' surfaces. When using coarse ferroelectric fillers, the probability of clustering is higher, thus favoring the permittivity increase by field concentration in small regions close to the interfaces separating dissimilar materials. The modeling results were validated by an experimental dielectric analysis performed in a series of PVDF-based thick films with the same amount of BaTiO 3 fillers or with Ag−BaTiO 3 hybrid fillers. Similar trends as predicted by simulations were found experimentally but with slightly higher permittivity values which were assigned to the modifications of the polymer phase composition due to the presence of nanofillers and the local sample inhomogeneity (the presence of clustering, in particular for coarse BaTiO 3 grains), which create regions with enhanced local fields.

Notably enhanced dielectric response with low loss in PVDF composites filled with RuO2–BaTiO3 hybrid particles

“…The XRD pattern of the hybrid particles displays prominent diffraction peaks attributed to nBT at 2θ ≈ 22°, 32°, 39°, 45°, 51°, 56°, 66°, 70°, 75°, and 79°, corroborated by JCPDS No. 01-075-0211 for BT phase [6,34]. However, the anticipated diffraction peaks of RuO 2 were not discernible within the observed pattern.…”

“…Polymer composites characterized by high dielectric permittivity (ε′) and low dielectric loss (tanδ) are instrumental in the advancement of electronic applications. Their distinctive attributes-including lightweight composition, cost-effectiveness, simplicity in fabrication, and versatility-render them highly attractive subjects for scholarly investigation and analysis [1][2][3][4][5][6]. Poly(vinylidene fluoride) (PVDF) and its copolymers predominantly serve as polymer matrices, owing to their significant ε′ value, which is approximately 10.…”

“…The integration of polymers, ceramics, and metal particles culminates in the creation of a three-phase polymer composite, effectively addressing the limitations encountered with traditional polymer composites. The surface modification of ceramic particles emerges as a noteworthy approach in the development of threephase composites, as documented in numerous studies [6,[23][24][25][26][27]. This technique potentially facilitates superior dielectric properties, characterized by high ε′ and reduced tanδ.…”

“…Notably, the deposition of metal particles onto ceramic surfaces can catalyze a significant increase in ε′, while concurrently inhibiting conductive pathways, thereby effecting a decrease in tanδ. In recent years, numerous three-phase metal nanoparticleceramic-PVDF composites have been extensively investigated, including Ag-BT-PVDF [6,24], Ag-Na 0.5 Bi 0.5 Cu 3 Ti 4 O 12 -PVDF [25], Au-BT-PVDF [28], Ag-LSNO-PVDF [29], Au-TiO 2 nanorod-PVDF [26], and Ni-BT-PVDF [22,30]. Among these, RuO 2 stands out as a transition metal oxide with remarkable properties as a metal particle, notably its high conductivity and superior chemical and thermal stability [31].…”

Two-Dimensional Metal-Organic Framework Incorporated Highly Polar PVDF for Dielectric Energy Storage and Mechanical Energy Harvesting

“…Moreover, different functional properties of nanomaterials can be incorporated into PVDF-based composites for the corresponding performance of the final device, along with the applications related to polarity. Inorganic oxides, due to their various physiochemical advantages and unique electronic and functional properties [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ], can be easily used as fillers in PVDF and hence under tremendous research attention in this regard [ 14 , 19 ].…”