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

This study delineates the process of fabricating and the results of investigating the dielectric properties of hybrid particles created through the integration of Poly(vinylidene fluoride) (PVDF) filled with RuO2 coated on BaTiO3 nanoparticles (nBT), designated as RuO2–nBT. These hybrid particles were successfully synthesized employing a simple and cost–effective solid–state reaction method. The inclusion of RuO2–nBT in the PVDF matrix engendered a notable enhancement in its dielectric properties. Notably, a RuO2–nBT fraction of 0.5 manifested a dielectric constant (ε′) of 107.4 and a dielectric loss tangent (tanδ) value of 0.062 at 30 °C and 1 kHz. These findings signify the effective role of interfacial polarization occurring between the PVDF matrix and the RuO2–nBT hybrid particles, leading to a marked improvement in dielectric attributes. Moreover, the observed low tanδ value indicates the elimination of conductive pathways, an inhibitory effect attributed to the incorporation of RuO2–nBT hybrid particles. This study underscores the promising potential of RuO2–nBT hybrid particles in fine–tuning and augmenting the dielectric properties of polymer composites, particularly in scenarios necessitating low tanδ and high ε′ values.


Introduction
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.This intrinsic property positions them as preferred materials in the construction of advanced electronic applications, fostering further innovations in the field [3,[7][8][9][10].Unfortunately, the ε′ values of PVDF and its copolymers are too low for use in electronic devices, particularly when aiming to reduce the capacitor size in embedded capacitors.Therefore, research focused on enhancing the dielectric response of PVDF polymer has become invaluable and has seen extensive exploration in recent years.Furthermore, while enhancing the dielectric response in a polymer matrix composite is essential, maintaining a low tanδ value is equally important.
Many research studies have explored improving the dielectric properties of PVDF composites by incorporating ceramic materials with exceptionally high ε′ values greater than 10 3 .A prevalent approach entails the fusion of PVDF with ceramics exhibiting high ε′, thereby capitalizing on the synergistic effects to achieve enhanced functional characteristics [3,4,[11][12][13][14].Research has demonstrated that a significant increase in ε′ can be achieved with specific modifications.However, the ε′ of these polymer composites remains relatively low, despite the incorporation of a substantial fraction of ceramic components ( f ceramic ).For instance, PVDF polymer filled with 50 vol% CaCu 3 Ti 4 O 12 (CCTO) [15].Its ε′ value was approximately 65 at 1 kHz and room 2. Experimental details 2.1.Preparation of RuO 2 -nBT hybrid particles RuO 2 , with a purity of 99.9%, and nBT, characterized by a cubic crystalline phase and particle sizes of less than 100 nm with a purity exceeding 99%, were procured from Sigma-Aldrich.Given the cost of RuO 2 , we aimed to utilize it in minimal amounts while still achieving optimal properties.Initially, 0.05 g of RuO 2 was combined with 4.5 g of nBT along with ZrO 2 balls in deionized water, stirring continuously for a period of 24 h at an ambient temperature of approximately 25 °C.Subsequently, the ZrO 2 balls were meticulously separated from the mixture.Following this step, the mixture underwent a heating process at a temperature of 100 °C for 24 h in an oven, facilitating the acquisition of dry mixed powders.In the final stage, the resultant powder was subjected to calcination at a temperature of 750 °C for a duration of 2 h, using heating and cooling rates of 5 °C min −1 to produce RuO 2 -nBT hybrid particles.It is important to note that that composites with 0.5 g of RuO 2 and 4.0 g of nBT were also prepared, applying identical processing conditions.However, despite the substantial amount of the pricier RuO 2 utilized, the anticipated enhancement in the dielectric properties of the RuO 2 -nBT/PVDF nanocomposites was not achieved due to elevated tanδ values, as depicted in figure S1 (supplementary information).
2.2.Preparation of RuO 2 -nBT/PVDF polymer composites PVDF polymer powder, having a molecular weight of approximately 534,000, was procured from Sigma-Aldrich.Initially, PVDF and RuO 2 -nBT hybrid particles were mixed with ZrO 2 balls, each 2 mm in diameter, in ethanol (C 2 H 6 OH, RCI Labscan, 99.7% purity).This mixing process was conducted for a duration of 3 h at an ambient temperature of approximately 25 °C.Subsequently, the ZrO 2 balls were carefully removed from the mixture.In the following step, the ethanol solution was subjected to evaporation at a temperature of 100 °C in an oven, sustained over a 24-h period.Lastly, the RuO 2 -nBT/PVDF composite powders, with RuO 2 -nBT filler volume fractions (f ) of 0.1, 0.2, 0.3, 0.4, and 0.5 were shaped into polymer composite samples through the utilization of a hot-pressing method.This process involved the application of a uniaxial compressive stress, approximating 10 N m −12 , at a temperature of 200 °C for a span of 30 min.At > 0.5, there was a marked loss of flexibility in the composite samples.This loss of flexibility led to the inability to form cohesive samples, as evidenced by the breakage of the samples when released from the mold after undergoing the hotpressing process.

Characterization techniques and dielectric measurement
Transmission electron microscopy (TEM, FEI, TECNAI G2 20 and FEI, Tecnai 12) was employed to scrutinize the particle shapes of both pristine nBT and the synthesized hybrid particles.To prepare the sample for TEM, the hybrid powders were sodicated in ethanol for 1 h.Subsequently, a drop of the suspension was placed onto a copper grid and allowed to dry at 80 °C for one h.To evaluate the phase composition of the RuO 2 , nBT, RuO 2 -nBT hybrid particles, and RuO 2 -nBT/PVDF nanocomposite samples, X-ray diffractometry (XRD) was performed using a PANalytical EMPYREAN instrument.For detailed insight into the cross-sections of the polymer composites, investigations were carried out using a field emission scanning electron microscope (FESEM), specifically the HITACHI SU-8030 model.Additionally, SEM mapping and energy-dispersive X-ray spectroscopy (EDX) techniques were utilized to detect all elements present within the composites.In addition, Fourier-transform infrared spectroscopy (FTIR), facilitated by the Bruker TENSOR27 system, was utilized to delineate the phase conformation present within the polymer composites.
A KEYSIGHT E4990A Impedance Analyzer played a pivotal role in exploring the dielectric properties of the samples under various frequencies (10 2 -10 6 Hz) and temperatures (−60 to 150 °C), employing an oscillation voltage parameter set at 500 mV.The investigation of the dielectric properties as a function of temperature was carried out in a DELTA 9023 environmental chamber.The temperature was incrementally increased in steps of 10 °C, with a temperature accuracy of ±0.1 °C.We selected the capacitance (C p )-dissipation factor (D or tanδ) mode for our measurements.This comprehensive analysis equipped us with a profound understanding of the intricate properties and potential applications of the developed materials.The thicknesses of the RuO 2 -nBT/PVDF nanocomposite samples with f n RuO BT 2 -= 0.1, 0.2, 0.3, 0.4, and 0.5 were approximately 0.21, 0.52, 0.54, 0.055, and 053 mm, respectively.Silver (Ag) paint was employed as the electrode material.The samples were uniformly coated on both sides with Ag paint and then dried at 80 °C for 2 h.The electrode area was approximately 0.5 cm 2 .Photographic images of the nanocomposites are presented in figure S2 of the supplementary information.

Results and discussion
The characteristics of RuO 2 -nBT hybrid particles were elucidated using TEM analysis compared to the TEM image of nBT.As depicted in figure 1(a), the pristine nBT particles exhibit a spherical morphology, with dimensions ranging between 50 and 100 nm.Additionally, figure 1(b) presents the TEM imagery of the RuO 2 -nBT hybrid particles, illustrating a composition of larger nBT entities accompanied by what are presumed to be smaller RuO 2 particles.Notably, RuO 2 particles, approximately 10 nm in size, were found to be uniformly dispersed on the surface of the nBT particles.These findings confirm that the RuO 2 -nBT hybrid particles were successfully synthesized.However, the presence of RuO 2 particles requires clearer confirmation.
Consequently, the XRD technique was employed to verify the RuO 2 phase in the RuO 2 -nBT hybrid powder, contrasting it with the nBT powder.101), ( 200), ( 211), ( 220), ( 002), ( 310), ( 112), (301), and (202) diffraction planes, respectively, of the RuO 2 phase, as indexed in the JCPDS file 00-021-1172.The relative intensities of the diffraction peaks were measured as 33.5%, 27.3%, 4.8%, 17.1%, 4.0%, 2.1%, 2.7%, 3.6%, 3.5%, and 1.5%, respectively, corresponding to their order of appearance or identification in the analysis.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.This can be ascribed to the markedly low concentration of RuO 2 in the sample, which is substantially overshadowed by the dominant presence of nBT, with a compositional ratio of RuO 2 to nBT being 1.10:98.90wt%.This pronounced disparity in constituent concentrations is the underlying reason for the non-detection of RuO 2 peaks in the XRD pattern of the RuO 2 -nBT hybrid particles.= 0.1, 0.2, 0.3, 0.4, and 0.5.The overall patterns closely resemble those observed in the XRD pattern of the RuO 2 -nBT hybrid powder.This similarity arises mainly due to the low crystallinity of the semicrystalline PVDF polymer compared to the higher crystallinity of the nBT ceramic powder.As mentioned, the compositional ratio of RuO 2 to nBT was very low, which further decreases upon incorporation into the PVDF polymer matrix.Consequently, the XRD peak of the RuO 2 phase is not present.
As is well known, the dielectric and electric properties of composite materials are closely correlated with their microstructure.The dispersion of filler particles is one of the key factors affecting these properties.Therefore, the microstructure of the RuO 2 -nBT/PVDF composites was further studied.The microstructure of the RuO 2 -nBT/PVDF composites is illustrated in figure 3, wherein cross-sectional images unveil the internal composition of the polymer composites.Figure 3 = 0.10.The imagery distinctly reveals the presence of the PVDF matrix within these composites.Furthermore, it is observed that the hybrid particles are uniformly dispersed throughout the PVDF matrix.The microstructural characteristics of polymer composites with f n RuO BT 2 -= 0.30 and 0.50 are depicted in figures 3(b) and (c), respectively.In both cases, the hybrid particles exhibit commendable dispersion within the PVDF matrix.However, it is crucial to note that a diminished PVDF matrix content, coupled with a heightened filler concentration, can foster aggregation of filler materials within the polymer composites.Such agglomerations potentially heighten tanδ and conductivity (σ) [16].Interestingly, in this composite system, the RuO 2 particles that are deposited on the nBT surfaces act as a deterrent to the agglomeration of nBT particles, effectively curbing the formation of conductive pathways [6].Consequently, this results in a substantial decrease in both tanδ and σ, showcasing the effectiveness of this structural configuration in maintaining desirable properties.
In our study, we demonstrate the advantages of using the conventional mixed oxide method for synthesizing RuO 2 -nBT hybrid particles over methods like hydrothermal synthesis [33], which struggles with scalability for large-scale production.The simplicity of conventional method, use of basic equipment, and reliance on water instead of toxic solvents like DMF [35,36] reduce costs, enhance safety, and improve environmental sustainability, making it ideal for electronics industry applications.The environmental advantages of the method include reduced contamination risks and simplified waste management, with minimal RuO 2 usage minimizing potential contamination.This approach aligns with stringent environmental regulations and supports the scalable production of hybrid particles without complex procedural changes.Considering the   environmental impact of RuO 2 , given its use in electronics, is critical.Although stability of RuO 2 and low solubility limit its environmental footprint, the release of nanoparticles could pose risks to ecosystems and human health.However, the low RuO 2 concentration used in our process, compared to BT and PVDF, may reduce these risks, emphasizing the need for responsible lifecycle management of RuO 2 -containing materials.
Given the disappearance of the RuO 2 phase in the XRD results, we attempted to confirm the existence of RuO 2 and to reveal the dispersion of RuO 2 -nBT hybrid particles within the PVDF polymer matrix using the SEM-EDX mapping technique.Figure 4  = 0.50.This analysis clearly delineates all the constituent elements present within the polymer composites.The PVDF matrix, characterized by the presence of carbon (C) and fluorine (F), forms a continuous phase, affirming the uniform integration within the structure.Furthermore, the constituent elements of nBT, namely Barium (Ba), Titanium (Ti), and Oxygen (O), are prominently represented, illustrating their substantial contribution to the composite material.Noteworthy is the evident presence of ruthenium (Ru), indicative of RuO 2 incorporation within the polymer composites.Hence, the SEM-EDX elemental mapping effectively substantiates the amalgamation of the PVDF matrix with the RuO 2 -nBT/PVDF hybrid particles, underpinning the successful creation of a complex, multi-component composite.
Figure 5 presents the EDX spectrum of the RuO 2 -nBT/PVDF composite with with a filler volume fraction = 0.50, clearly illustrating the presence of RuO 2 within the PVDF matrix and amidst the nBT particles.The spectrum indicates the existence of RuO 2 particles, each with a size of less than 20 nm, embedded within the PVDF matrix.
Typically, in ceramic-PVDF composites, identifying the phases of the semicrystalline PVDF polymer using the XRD technique can be challenging due to the strong XRD peak intensities of polycrystalline ceramics [26].Instead, the FTIR technique is commonly employed to discern the PVDF phases present in the composite matrix [10,37].The FTIR results unveil the phase conformations present within the PVDF matrix and the polymer composites, as illustrated in figure 6(a).The spectra distinctly showcase α-, β-, and γ-phase conformations in the PVDF matrix.Wavenumbers approximately at 614, 766, 795, and 976 cm − ¹ correspond to the α-phase, as noted in references [10,37,38].Meanwhile, the β-phase is discernible at wavenumbers around 840 and 1279 cm − ¹, and the γ-phase is evident at about 840 cm − ¹ [10,37,38].It is significant to highlight that the polymer composites retain the identical phase conformations as observed in the pristine PVDF matrix.Furthermore, a noteworthy difference is perceived in the polarity of these phase conformations; the α-phase exhibits non-polar characteristics, whereas the βand γ-phases are polar in nature.Particularly, the presence of the polar β-phase within the polymer matrix potentially elevates the ε′ value, attributable to the dipole polarization inherent in the PVDF matrix.In light of this, an in-depth investigation into the relative content of the β-phase (denoted as F(β)) within the polymer matrix was undertaken.Utilizing the Lambert-Beer equation, which presupposes the existence of only the αand β-phases in the polymer composites [10], F(β) was calculated as per the equation below: Here, A α and A β denote the absorbance values of the αand β-phases at wavenumbers 766 and 840 cm − ¹, respectively.Furthermore, the absorbance coefficients are given as K α = 6.1 × 10 4 cm 2 mol −1 for the α-phase, and K β = 7.7 × 10 4 cm 2 mol −1 for the β-phase.a consequence of the enhanced phase transformation to the β-phase (all trans, TTT configuration), facilitated by the interaction between negatively charged hybrid particles and the PVDF polymer [10,37,39].Nevertheless, it is critical to acknowledge that an overabundance of hybrid particles can potentially restrain β-phase conformation [40], ulminating in diminished F(β) values within the polymer composites.Nevertheless, all the  composites exhibit the presence of the polar β−phase, which is typically favored for enhancing the dielectric response in PVDF polymer matrix composites.
Consequently, we investigated the dielectric properties of the RuO 2 -nBT/PVDF composites to understand the impact of the RuO 2 -nBT hybrid particles and to pinpoint potential applications for these composites.The dielectric properties as a function of frequency were analyzed within the frequency range of 10 2 − 10 6 Hz, with the observations illustrated in figure 7(a).Notably, the ε′ exhibited a downward trend with the escalation in frequency.In the context of lower frequencies, a marginal decline in ε′ was registered, especially for polymer composites possessing high concentrations of (specifically where f n RuO BT 2 -= 0.4 and 0.5).onversely, a pronounced decrease in ε′ was recorded across all samples at elevated frequencies.This downward trajectory of ε′ can be rationalized through the underlying mechanisms operating within the polymer composites, wherein the manifestations at low and high frequencies can be attributed to interfacial and dipole polarization phenomena, respectively [16,41].Shifting focus to figure 7(b), it sheds light on the frequency-dependent behavior of the tanδ.In the low-frequency regime, tanδ values remained below 0.1, escalating significantly within the higher frequency brackets (ranging from 10 5 − 10 6 Hz).It is pertinent to note that the emergence of a relaxation peak at high frequencies is inversely correlated with the decrement in ε′ [16,42].Furthermore, the diminished tanδ observed in polymer composites when f n RuO BT 2 -= 0.5 signifies the preeminence of dipole polarization at higher frequency intervals, highlighting a more dominant role in influencing the dielectric response of the material.
To clearly illustrate the effect of RuO 2 -nBT concentration on the dielectric and electrical properties, the dielectric parameters and AC conductivity are represented at 1 kHz and 30 °C.The ε′ and tanδ values of the RuO 2 -nBT/PVDF composites, at varying levels of f , are illustrated in figure 8.The data reveals a substantial increase in the ε′ values of the polymer composites compared to the baseline ε′ of the PVDF matrix, which is 11.81.Specifically, the ε′ values registered were 30.2, 46.3, 60.1, 76.4, and 107.4 for polymer composites  = 0.1, 0.2, 0.3, 0.4, and 0.5, respectively.This uptrend signals that the incorporation of RuO 2 -nBT hybrid particles significantly elevates the ε′ of the polymer composites.Furthermore, it can be observed that the ε′ linearly increased with increasing f .
It is noteworthy that there was no rapid change observed in the ε′.Consequently, the substantial enhancement in the dielectric response cannot be attributed to percolation theory [22].Instead, the significant increase in ε′ values is primarily due to interfacial polarization at the interfaces between the conductive RuO 2 -nBT and the RuO 2 -PVDF polymer matrix.This significant increase in dielectric response is comparable to those observed in PVDF-matrix composites that were filled with metal nanoparticle-high permittivity ceramic particles, such as such as Ag-nBT/PVDF [6,24], Au-nBT/PVDF [28,35], Au-TiO 2 nanorods/PVDF [26], and Ag-Na 1/2 Bi 1/2 Cu 3 Ti 4 O 12 /PVDF [25].When an electric field is applied, free charges in the RuO 2 particles migrate, accumulating at the insulating interfaces, which results in pronounced interfacial polarization at the junctions between insulating and conducting phases, each exhibiting different polarities.This leads to an increase in the ε′ values of the polymer composites.Therefore, the augmentation in ε′ n the RuO 2 -nBT/PVDF composites can be ascribed to the synergistic effects of interfacial polarization taking place among various components [6,24,43]: PVDF-nBT particles, PVDF-RuO 2 particles, and RuO 2 -nBT particles.Additionally, the improved ε′ values as the filler volume fraction increased can also be partially attributed to the enhanced high-permittivity nBT phase, following to a simple mixing rule.
For capacitor applications, an enhanced dielectric response should not coincide with an increase in tanδ.In other words, tanδ should be maintained at a low value (below 0.1).As shown in figure 8, the tanδ values at 1 kHz and 30 °C were 0.021, 0.034, 0.052, 0.064 and 0.062 for the polymer composites with f n RuO BT 2 -= 0.1, 0.2, 0.3, 0.4, and 0.5, respectively.Note that the tanδ value of a PVDF polymer were 0.02.It was shown that the tanδ values were lower than 0.1.Similarly, polymer composites have the low σ in the range of 10 −9 − 10 −10 S cm −1 , as displayed in in the inset figure 8.It is worth noting that the tanδ value exhibited a minor increase from approximately 0.021 to 0.064, as the increased from 0.1 to 0.4.However, upon further increase from 0.4 to 0.5, tanδ slightly decreased from 0.064 to 0.062.This trend demonstrated a significant rise in the ε′, while maintaining a relatively low tanδ value.The observed minimal increase, and subsequent slight reduction in tanδ with increased filler concentration, can be attributed to the discrete distribution of RuO 2 nanoparticles on the nBT surface.This discrete attachment hindered the formation of a continuous conduction pathway for the RuO 2 particles, thereby limiting the long−range motion of free charges, which is typically associated with higher tanδ and conductivity.As a result, the tanδ value remained low and exhibited only a slight increase with increased filler loading.This is because a hybrid structure, in which RuO 2 can suppress the agglomeration of the nBT particles and inhibit the conductive pathways of polymer composites [24].The attraction of RuO 2 nanoparticles to the surface of nBT can lead to a reduction in surface free energy.This effect is similar to that observed in other PVDF−matrix composites filled with hybrid particles, where nBT is coated by metal nanoparticles [24].Moreover, to mitigate the agglomeration of filler nanoparticles, further investigations involving the use of surfactants or other dispersing agents are warranted.For instance, the well−dispersed CaCu 3 Ti 4 O 12 treated with γ−aminopropyl triethoxy silane in the polymer matrix significantly enhanced the dielectric properties [44].Recent studies have also demonstrated that the inclusion of surfactant−assisted fillers can improve the dielectric properties of the PVDF polymer matrix [45].It is worth noting that, for a given volume fraction of fillers, the ε′ value of the RuO 2 -nBT/PVDF composites exceeded that of the nBT/PVDF composites.Additionally, the tanδ value of the RuO 2 -nBT/PVDF composites was below that of the nBT/PVDF composites, as shown in figure S3 of the supplementary information.These results indicated the important role of RuO 2 to enhance the dielectric response in the composies.The dielectric parameters (ε′ and tanδ) at 1 kHz and RT were summarized in table 1 compared to those reported in previous works.
Previous research has delved into 3-phase polymer composites utilizing hybrid particles and noted a significant enhancement in the value of ε′.For instance, a study on the 10 vol% (Au-BT)/PVDF composite reported a ε′ value of approximately 11.9 and a tanδ f about 0.027 [41].Another investigation concerning 0.33(BT-Fe 3 O 4 )/PVDF documented ε′ and tanδ values of 280 and 0.27, respectively [46].It is noteworthy that many of these studies recorded low values for ε′.Nonetheless, a trend was identified where an increase in ε′ would usually coincide with a rise in tanδ.onsequently, it has been demonstrated that the dielectric properties of RuO 2 -nBT/PVDF composites can be optimized, showcasing high ε′ and low tanδ values.
To explore potential applications in capacitors, we investigated the temperature dependence of the dielectric properties, as this is a critical factor in determining the suitability of dielectric materials for practical use.Furthermore, understanding the temperature−dependent behavior of dielectric properties is essential.The RuO 2 -nBT/PVDF composites were analyzed across a temperature range of −60 to 150 °C, as illustrated in figure 9.The data indicated a consistent increase in ε′ as the temperature rose.At lower temperatures (−60 to 0 °C), the observed increase in ε′ could be attributed to the β relaxation phenomenon.Conversely, the α relaxation process predominantly accounted for the heightened ε′ at elevated temperatures.The tanδ values unveiled a notable β relaxation peak at lower frequencies, aligning with the respective ε′ values, while the α relaxation peak became evident at higher temperatures.These β and α relaxation phenomena are fundamentally linked to the dipolar rotation and the molecular movements within the PVDF matrix [24,47,48].Moreover, the findings propose that the underlying mechanisms governing the behavior of these polymer composites involve

Conclusions
In this research, RuO 2 -nBT/PVDF composites were meticulously fabricated and an analysis was conducted to study the impact of RuO 2 -nBT hybrid particles on the dielectric properties of the composite material.The findings confirm that RuO 2 -nBT hybrid particles can indeed be synthesized successfully using a simple and inexpensive method, consequently enhancing the dielectric properties of the polymer composites.Specifically, the polymer composites containing RuO 2 -nBT with f n RuO BT 2 -= 0.4 and 0.5 demonstrated the ε′ values of 107.4 and 76.4, respectively at 1 kHz and 30 °C, while tanδ values of 0.064 and 0.062, respectively.These results signify that the enhancement in dielectric properties can be attributed to the interfacial polarization occurring between the PVDF matrix and the RuO 2 -nBT hybrid particles.Furthermore, the observed low tanδ value hints at the absence of conductive pathways, a phenomenon suppressed by the incorporation of RuO 2 -nBT hybrid particles, thereby maintaining the integrity of the composite's insulating properties.Detailed analysis on the dependence of dielectric properties on frequency and temperature revealed that the effects of interfacial polarization are predominantly observed at lower frequencies and elevated temperatures.The RuO 2 -nBT/PVDF composites, exhibiting significantly enhanced ε′ and reduced tanδ, may have potential for use in embedded flexible capacitors.

Figure 2 (
b) displays the XRD patterns of the RuO 2 -nBT/PVDF composites with f n RuO BT 2 - (a) delineates the microstructure of the polymer composites where f n RuO BT 2 -
presents the SEM-EDX elemental mapping of the RuO 2 -nBT/PVDF composites, where f n RuO BT 2 -

Figure 6 (
b) visually portrays the F(β) values across the polymer composites, highlighting a substantial 46% F(β) presence within the unadulterated PVDF matrix.Furthermore, an escalating trend in F(β) values is observed for polymer composites infused with varying fractions of f , n RuO BT 2 -

Table 1 .
Comparison of ε′ and tanδ (at 1 kHz and ∼25 °C-30 °C) for PVDF matrix composites with various types of fillers compared to the RuO 2 -nBT/PVDF composites.