Dielectric properties of synthesized ternary hybrid nanocomposite embedded in poly (vinyl alcohol) matrix films

Abstract

This research involves preparation and characterization of ternary hybrid nanocomposites; reduced graphene oxide rGO nanosheets, manganese dioxide MnO₂ nanorods and poly (anthranilic acid) hollow sphere PANA (rGO-MnO₂-PANA). The synthesis follows bi-step chemical reaction. Initially, rGO and MnO₂ were prepared separately, then mixed together ultrasonically to form a binary hybrid of rGO-MnO₂. Second step includes in situ polymerization of anthranilic acid monomer with the prepared rGO-MnO₂. All the prepared compounds were characterized by different techniques: FT-IR, XRD, SEM, EDX and TEM. Incorporation of the ternary hybrid in different weight ratios with PVA afforded the required nanocomposites (rGO-MnO₂-PANA/PVA) films. The electrical properties of the nanocomposite films were investigated at frequency of 10 kHz-2 MHz. It was found that, at low frequency, the dielectric (real) permittivity (ε’) and imaginary permittivity (ε”) approached to higher values in all cases, while these values decreased gradually with increasing frequency. It was also confirmed that the alternating current conductivity of the composites increased with increasing frequency. These findings underline the potential employing of rGO-MnO₂-PANA/PVA composites as a flexible dielectric material for enhancing polymer electrical conductivity and in energy storage applications.

Keywords

Reduced graphene oxide (rGO)polyanthranilic acid ternary hybrid nanocomposite electrical properties

Introduction

Polymers nanocomposite are highly attractive material as they show promising properties for assortment of various applications.^1,2 They are conventionally prepared by blending polymers, as matrices, with conductive nanofillers to disclose unique physical properties.³ Practically, metal oxides and carbon nanostructure, particularly, reduced graphene oxide (rGO) have been anticipated as nanofillers due to its feasible benefits and its scarce properties like large specific surface area, high carrier mobility and excellent electrical conductivity.^4,5 In fact, the conductive nanofillers act as charge transport and are supposed to modify constructions of nanoscale devices.^6,7 Therefore, (rGO) is very appropriate for reinforcing the features of the polymers host and has become an essential material for sensors devices, energy storage and conversion. Regardless of that prosperity, there is still some impedance facing establishment of rGO sheets in polymers.^8,9 It is rather tricky to achieve high dielectric properties of rGO/ polymer composites. It requires adjusting the quantity of the graphene filler, since little alteration in the magnitude of the conductive filler would provoke a spectacular variation of the percolation threshold. The poor distribution and compatibility between the rGO and the polymer matrix impedes the formation of a homogeneous composite solution. That would result in re-aggregate of the rGO and consistence vacancies at the interface of the filler with matrix and disturb the device applications. Furthermore, the dielectric loss (tan δ) in the conductive filler/polymer composites always appears to be very important because of the current leakage through the conductive fillers.^10,11 In order to overcome these drawbacks, rGO has been combined with conducting polymers and metal oxides to block its sheets aggregation and reinforce the electron transfer as well as improve the dielectric merits.^12,13 This combination provides hybrid nanocomposite materials which promote the physical properties of the polymer matrix for varied utilization like energy storage, microelectronics, sensing,…etc.^9,13,14 Accordingly, many reports have been published on study of dielectric properties of metal oxide and/or rGO-based conductive polymers nanocomposites.^15,16 Among the best conducting polymers, polyaniline (PANI) has received considerable attention due to its easy preparation and the elegant electrical property. Its quality excitingly boosted by addition of tiny amount of organic or inorganic nanofillers.^12,15 In contrast, the commercial use of PANI is being restricted due to its insolubility in most familiar solvents and its infusibility. So, fabrication of PANI/ nanocomposite films for industrial scale may need employing harmful solvents in which turn rise environmental damage.^17,18 In this context, new strategies have been directed to synthesis flexible dielectric composites composed of PANI /nanofiller (rGO and/or Metal oxide) established with polyvinyl alcohol (PVA) as a host. PVA using is counted on being a high transparency, anti-electrostatic properties, chemical resistance, good flexibility and capability of film forming. Moreover, it is being water soluble, thus, would activate and stabilizes the dispersion of the nanofiller much easier.^19-21 In relation to the above remarks, we choose poly(anthranilic acid) (PANA), one of PANI derivatives with carboxylic acid group, as an alternative to the PANI. Despite of its low electro-active property^17,18,22 it possesses a high processibility and solubility in aqueous solutions, alcohol and polar solvents. In addition, the carboxylic acid group has the ability to self-doping by oxidation and reduction process, thereby, supply more pattern of charge storage for the supercapacitor use.²² Thus, the main objective of the current work was to focus on preparation of ternary hybrid nanofiller structured of poly(anthranilic acid) (PANA) hallow sphere, MnO₂ nanorods and reduced graphene oxide (rGO) (rGO-MnO₂-PANA) then applied it to modify PVA electrical performance. The synthesis initially achieved by consistence of rGO-MnO₂ binary composites which has been used as an efficient energy storage electrode material.^23-25 Whereas, the PANA hallow sphere was polymerized in situ with the rGO-MnO₂ binary composites. All the nanocompouds were characterized by FT-IR, XRD, EDX, SEM and TEM techniques. Finally, the as-prepared hybrid was, then, established in the PVA matrix to fabricate nanocomposite-PVA films, followed by assessment of the electrical properties by using the LCR. The experimental data were submitted on the evaluation of dielectric properties and AC conductivity for all doped films.

Experimental

Materials and physical measurements

Materials

The starting materials were obtained from various sources and companies: manganese sulfate (Merck KGaA, Darmstadt, Germany), concentrated nitric acid (Merck KGaA, Darmstadt, Germany), graphite (Alpha Chemika, Maharashtra, India), potassium permanganate, concentrated sulphuric acid (98%), hydrochloric acid (36%), potassium hydroxide, and PVA (Sigma-Aldrich, Taufkirchen, Germany, hydrogen peroxide (30%) (HIMEDIA, Mumbai, India) and hydrazine monohydrate (Qualikems, Gujarat, India).

Instrumentation

Fourier transform infrared (FTIR) spectra of the GO, rGO, MnO₂ nanorods, PANA, rGO-MnO₂ and rGO-MnO₂-PANA nanocompounds were recorded by 65 FT-IR Perkin Elmer Spectrophotometer, Waltham, Massachusetts, USA. The samples were incorporated in a KBr disk and measured over the range of 4000–400 cm ⁻¹ . The X-ray diffraction (XRD) analyses for the GO, rGO, MnO₂, rGO-MnO₂ and rGO-MnO₂-PANA nanofillers were carried out by (Shimadzu-XR-6000, Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto 604-8511, Japan) with a nickel-copper filter for the X-ray radiation (copper Kα, λ = 1.5406 A°). The morphology of the as-prepared samples was observed by scanning electron microscopy (SEM) in two different research centers using (TESCAN, MIRA3, Brno, Czech Republic at Sharif University of Technology/Iran), which used for the samples (MnO₂ and rGO-MnO₂), while the samples (PANA and rGO-MnO₂-PANA) were measured by the same type of instrument at (Bartin University/Turkey). The TEM were recorded by (Zeiss, EM10C-100 KV, Germany/Day Petronic Co.). The Precision LCR meter (GW INSTEK LCR-8105G, New Taipei City, Taiwan) was used for the dielectric properties for all prepared films in frequency range of (10kHz-2 MHz)

Preparation of materials

Preparation of reduced graphene oxide (rGO)

Graphene oxide (GO) was prepared following a modified Hummers method from pristine graphite powder.²⁶ Reduced graphene oxide (rGO) was obtained through reduction of the prepared GO by using hydrazine hydrate as following: an inhomogeneous dispersed aqueous solution of GO 100 mg in deionized water 100 mL was loaded in a 250 mL round bottomed flask. The solution was sonicated for 30 min using ultrasonic water bath. Then, hydrazine hydrate 1 mL was supplemented and the mixture was condensed at 100°C under stirring for 24 h. The rGO product gradually precipitated out as a black powder. The product was filtered, washed with deionized water several times to remove the residual traces of hydrazine, thereafter, dried at 80°C for 24 h.²⁷

Preparation of manganese dioxide (MnO₂) nanorods

Manganese dioxide MnO₂ nanorods was prepared by mixing aqueous solutions of potassium permanganate 3.68 g and manganese sulfate MnSO₄.2H₂O 5.5 g at ambient temperature. Then, concentrated HNO₃ was added to the reaction vessel to adjust the solution pH to approximately 1. The reaction product was then aged at 80°C for 24 h. The precipitate was filtered, washed by distilled water until the pH becomes 6 and the product was dried at 110^°C.²⁸

Synthesis of the (rGO-MnO2) nanocomposites

The di-nanocomposite hybrid of rGO-MnO₂ was prepared by dispersion of reduced graphene oxide (0.1 g) in deionized water (100 mL) using ultrasonic bath at 25°C for 1 h. Then, MnO₂ nanorods (0.1 g) were added and the mixture was left under fixed stirring for 2 h, thence sonicated for another 1 h. The precipitate was extracted by centrifuge and dried overnight at 80°C to attain the hybrid nanocomposite. The reaction pathway chart for the synthesis is shown in Figure 1.

Figure 1.

Schematic diagram for synthesis of reduced graphene oxide-manganese binary composite.

Synthesis of polyanthranilic acid (PANA) hollow sphere

Anthranilic acid (1.37 g) was oxidized by ammonium persulfate (APS) (2.85 g) in aqueous solution of acetic acid at room temperature. Initially, anthranilic acid monomer was added to a concentrated (1 M) of acetic acid (50 mL) with fixed stirring using magnetic stirrer. The oxidizing agent (dissolved in distilled water 50 mL) was, then, added dropwise to the monomer solution. After complete addition, the mixture was left under steadiness stirring for 24 h at room temperature. The product was filtered, washed by acetic acid at concentration of (1 M), then, with deionized water for several times to remove the acid residue. The isolated precipitate was left for dryness at room temperature for 48 h.¹⁷

In Situ Synthesis of rGO-MnO₂-PANA

The ternary nanocomposite rGO-MnO₂-PANA was synthesized by dispersion of rGO-MnO₂ (0.5 g) in deionized water (100 mL) using ultrasonic bath at 25°C for 1 h. Then, anthranilic acid monomer (3 g), dissolved in acetic acid 100 mL (1 M), was added and the mixture left under steadiness stirring for 1 h. Afterward, a solution of oxidizing agent (APS) (6.0 g) in acetic acid 100 mL (1 M) was added dropwise to the above mixture and left under stable stirring for another 24 h. The precipitate was filtered, washed with acetic acid (1 M) followed by deionized water and kept overnight in vacuum oven for drying at 80°C. The suggested chemical reactions are represented in Figure 2.

Figure 2.

Schematic illustration for the synthesis of rGO-MnO₂-PANA.

Fabrication of rGO-MnO₂-PANA/PVA nanocomposite films

Poly (vinyl alcohol) PVA composite films were cast with different weight percent of the rGO-MnO₂-PANA hybrid. An amount of PVA (2 g) was dissolved in warm distilled water (20 mL) and the desired quantity of the rGO-MnO₂-PANA (1%-5%), dispersed in distilled water 5 mL was added. The mixture was vigorously stirred for 1 h with warming up to 50°C to form a homogeneous solution. Subsequently, the solution was sonicated for 15-25 minutes at room temperature before casting onto a glass plate, thence, dried under vacuum at 60°C. Finally, the nanocomposites-PVA based films were peeled off and dried to study their dielectric properties.

Dielectric constant measurements

The fabricated films were cut as a circle pieces with radius equal to 3 cm to measure the dielectric properties using Precision LCR meter type (GW INSTEK LCR-8105G). The dielectric parameter as a function of frequency is defined by the complex permittivity.^29-31 The investigations were made at different frequencies (10 kHz-2 MHz) at room temperature. The dielectric parameter, as a function of frequency f, is described by the complex permittivity equation

ε^{*} (ω) = ε' (ω) - ε ″ (ω)

where the real (ε’) and imaginary (ε”) dielectric constant are the energy storage and loss elements, respectively, in each cycle of the electric field. The (ω) represent the angular frequency; ω = 2πf, f is the applied frequency. The calculated capacitance, (C) was used to determine the dielectric constant (ε’) by the following equation:

ε' = \frac{C d}{ε^{\circ} A}

where (d) is the thickness between the two electrodes (film thickness), (A) is the area of the electrodes, (ε₀) is permittivity of the free space = 8.85 10⁻¹² F.m⁻¹.

While the dielectric loss ε”(ω) and tan (δ) were estimated by the equation:

ε ” (ω) = ε' (ω) . tan δ (ω)

The ac conductivity (σ ac) can be calculated by the following equation:

σ = ε_{0} ε' ω tan δ

Results and discussion

Characterization of the prepared materials

FTIR

The FTIR spectra in Figure 3 are presenting the GO, rGO and MnO₂ nanocomponds. The spectrum of GO show the peaks at 3413, 1725, 1635, 1180 and 1052 cm⁻¹, Figure 3(a), related to the ν(O-H), ν(C=O), (O-H)/ ν(C=O) deformation of the unoxidized graphite, ν(C-O-C) and ν(C-O), respectively. The chemical reduction of GO may afford the rGO nanosheets as observed in FTIR spectrum Figure 3(b). The absence of the main bands of ν(O-H), ν(C-O-C), ν(C-O) and the reduction in the ν(C=O) band intensity with the appearance of the distinctive ν(C=C) band at 1566 cm⁻¹, refer to the rGO nanosheets formation.³¹ Furthermore, the FTIR spectrum of MnO₂ nanorods Figure 3(c) reveals the vibration bands at 522 and 459 cm⁻¹ which belong to the ν(Mn-O-Mn).³²

Figure 3.

FTIR spectra of (a) GO, (b) rGO and (c) MnO₂ nanorods.

Figure 4 displays the FTIR of the rGO-MnO₂, PANA and rGO-MnO₂-PANA nanostructures. Figure 4(a) shows the bands at 1623 and 579/531 cm⁻¹ belongs of ν(C=C) of the rGO and the bands of ν(Mn-O-Mn,) respectively. It can, also, easily to recognize the ν(Mn-O-Mn) bands were shifted to a higher frequency from those found in the pure one. This finding may indicate a successful anchoring of MnO₂ nanorods on the rGO nanosheets.

Figure 4.

FTIR spectra of (a) rGO-MnO₂, (b) PANA and (c) rGO-MnO₂-PANA.

In addition, Figure 4(b) represent the FTIR of the PANA which pursue the bands at 3353, 1683, 1603, 1510 and 1237 cm^–1, corresponding to ν(N-H), ν(C=O), ν(C=C) of the quinoid, ν(C=C) of the benzenoid and ν(C-H), subsequently. These findings are in accordance to the previous reported results.³³

Finally, the FTIR of the ternary rGO-MnO₂-PANA nanomaterial hybrid Figure 4(c) include all the characteristic bands of PANA at 3401, 1602, 1522 and 1276 cm^–1, in addition to the bands at 1686 and 528/492 cm^–1 of the ν(C=C) related to rGO and the ν(Mn-O-Mn) belong to MnO₂ nanorods, respectively. These bands are identifying the efficient association of the suggested ternary nanocomposite hybrid.

XRD

The XRD of the GO Figure 5(a), shows a strong and sharp peak at 2θ = 10.0981 corresponding to an interlayer distance of 7.6 Å (002). While, the pattern for the rGO Figure 5(b) show a broad peak which can be fitted by using a Lorentzian function into three peaks centered at 2θ (24.8114, 26.5084 and 42.3429). This outcome refer to an amorphous state of rGO with interlayer distances of (3.58558, 3.35977 and 2.13285) Å, respectively.^34,35

Figure 5.

XRD of (a) GO and (b) rGO.

On the other sides, the XRD of MnO₂ nanorods Figure 6(a) shows reflections of 2θ at (12.6734, 18.0281, 28.6951, 37.5307, 41.8776, 49.6584, 55.8058, 60.0293, 65.3576, 69.1015, and 72.9604^o) which may be attributed to the [(101), (200), (301), (211), (310), (411), (600), (512), (020), (514), and (312)] diffraction planes, respectively. These values agree well with the diffraction peaks of the crystal planes indexed of α –MnO₂ (JCPDS card PDF file no.44-0141).³⁶ Furthermore, the XRD pattern of the bi-components rGO-MnO₂ includes the diffraction peaks of both nano-constituents, rGO and MnO₂, as evident from Figure 6(b).

Figure 6.

XRD of (a) MnO₂ nanorods, (b) rGO-MnO₂ and (c) rGO-MnO₂-PANA.

In regard to the XRD pattern of the ultimate nanocompound rGO-MnO₂-PANA, Figure 6(c) shows the manganese oxide peaks that were observed in Figure 6(a). Besides, the other peaks (14.8713, 17.8532, 19.0458, 21.4125, 21.9641, 25.0007, 26.0674, 29.9504, 33.7564, 51.3651 and 53.6692^o) distinguish the involvement of the PANA polymer within the hybrid structure.¹⁸ The pattern, also, displays a crystalline state of the rGO-MnO₂-PANA as one can notice that from the sharpness of the peaks, rather than the manifested broad peak of the rGO-MnO₂, Figure 6(b). However, the rGO presence has been clearly confirmed by SEM, which will be discussed later.

Electron microscopy analysis The SEM/EDX

The SEM investigation of the polyanthranilic acid Figure 7(a, b) illustrates a hollow microspherical structure within the diameter range of 1.5 to 7.5 micrometers. It shows a hollow microspherical peel thickness of 100 nm which reveal that the polymer in nanoscale dimensions. While, the SEM of the prepared manganese dioxide Figure 7(c, d) verifies the rod-like structure in a width of 40 nm. Similarly, the SEM pattern of rGO-MnO₂ Figure 7(e) shows a sheet of rGO incorporated with the MnO₂ nanorods. These results, in addition to the XRD pattern Figure 6(b) for the binary nanocomponent are clear evidence for the interaction of MnO₂ nanoroads on the rGO nanosheets. Likewise, the SEM test of rGO-MnO₂-PANA Figure 7(g) shows irregular structure due to the domination of the PANA which overlay the rGO-MnO₂. However, the EDX has been carried out to determine the elemental composition of both rGO-MnO₂ and rGO-MnO₂-PANA nanocomposites and are shown in Figure 7(f, h). The profile of rGO-MnO₂ in Figure 7(f) listed the content of carbon signal, oxygen peak and three signals of manganese by weight percent ratio of 51.52 wt%, 33.32 wt% and 15.16 wt%, respectively. While Figure 7(h) display the content of carbon signal in a 51.61%, oxygen peak in a 39.05%, nitrogen peak in a 6.18%, which arise from the PANA, and other three signals of 2.83% manganese of the rGO-MnO₂-PANA. These findings confirm the ternary nanocomposition is in outstanding agreement with the results published elsewhere.³⁷

Figure 7.

SEM of (a, b) PANA, (c, d) MnO ₂ and (e) rGO-MnO ₂ , (f) EDX of rGO-MnO ₂ , (g) SEM of rGO-MnO ₂ -PANA, (h) EDX of rGO-MnO ₂ -PANA.

The TEM

Figure 8 exhibits the TEM micrograph of the rGO-MnO ₂ -PANA nanocomposite. The profile dose showing the accumulation of MnO ₂ nanorods beneath the PANA and the later superimpose the rGO-MnO ₂ binary nanocoposite. Based upon the aforementioned electron microscopy perception it seems that the ternary hybrid nanocomponents have been successfully prepared.

Figure 8.

TEM micrographs of rGO-MnO ₂ -PANA (a) in 500 nm magnification (b) in 200 nm magnification.

Electrical properties

The dielectric permittivity (ε’), imaginary permittivity (ε”), loss factor (tan δ) and electrical conductivity of the PVA films loaded with (1wt%-5wt %) rGO-MnO₂-PANA nanohybrid were investigated as a function of the frequency 10kHz-2 MHz. The results are summarized in Table 1 and Figures 9 (a-d). The profile indicate that both dielectric and the imaginary permittivity values for the pure PVA matrix and the loaded films were progressively decreased with increasing the frequency, Figure 9 (a, b). The films are, also, exhibited a typical dielectric properties percolation insulator-semiconductor transition behavior as the dopant concentration precedes more than 4%. In spite of boosting the dielectric permittivity of the embedded films by addition of the 1wt%-4wt % ternary hybrid, the permittivities of all films are retaining low values with increasing the frequency. On the contrary, the loss factor (tan δ = ε”/ε’), the energy dissipation magnitude,³⁸ account higher values for all films at a low frequency; thereafter decreases gradually with increasing frequency Table 1 and Figure 9 (c).

Table 1.

The dielectric permittivity (ε’), (b) imaginary permittivity (ε”), (c) loss factor (tan δ) and conductivity (σ ac) values of the PVA composites films with different concentrations of the nanofiller as a function of frequency.

No.	Doping percent	Frequency	ε’	ε”	tan δ	σ _{AC S/m}
1	pure PVA	10 kHz	1.905656	0.45351	0.2379	3.81 E-7
1	pure PVA	2 MHz	1.28273	0.22408	0.1746	1.22 E-6
2	1%	10 kHz	2.063564	0.86075	0.4171	1.61 E-7
2	1%	2 MHz	1.427937	0.29805	0.2087	1.51 E-6
3	2%	10 kHz	4.432523	2.63167	0.5937	3.68 E-7
3	2%	2 MHz	2.76103	0.71316	0.2583	3.54 E-6
4	3%	10 kHz	11.99028	10.0051	0.8338	2.23 E-5
4	3%	2 MHz	3.79225	1.17629	0.3101	1.84 E-5
5	4%	10 kHz	17.5945	15.2208	0.8650	4.18 E-5
5	4%	2 MHz	6.4038	1.31340	0.2051	4.39 E-5
6	5%	10 kHz	45.0721	39.4068	0.8743	6.02E-4
6	5%	2 MHz	8.35998	5.87695	0.7029	7.65E-4

Figure 9.

(a) Dielectric permittivity (ε’), (b) imaginary permittivity (ε”), (c) loss factor (tan δ) and (d) the conductivity of the PVA composites films in different concentrations of the nanofiller as a function of logarithmic frequency.

The high value of (ε’) and (tan δ) for the polymer composites with 5 wt% of the nanofiller may arise due to the dispersion of the filler in the polymer composite. Such dispersion offer different mechanisms of the dielectric properties. However, according to Maxwell–Wagner–Sillars (MWS) effect, for conductive nanofillers /polymer composites, when the current flows from the interface of the composites the space charges will gather conducting interfacial polarization. Thus, a huge increase in the permittivity is come across near percolation threshold. So, this effect has a crucial part in the dielectric constant of the rGO-MnO₂-PANA/PVA nanocomposite. Consequently, higher content of conductive fillers could construct more conductive paths and result in more current leakage and dielectric loss.^38,39

Electrical conductivity

The electrical conductivity of the rGO-MnO₂-PANA/PVA films is plotted as a function of the nanofiller content at different frequencies, Figure 10. The figure shows a direct relationship between the electrical conductivity and frequency. Incorporation of 1 wt.% rGO-MnO₂-PANA the conductivity was 1.61 × 10⁻⁷ S/m at low frequency 10 kHz, while the incorporation of 5%wt. the conductivity became 6.02 × 10⁻⁴ S/m at the same frequency. Furthermore, the conductivity of the 5 wt.% nanofiller establishment turn into 7.65 × 10⁻⁴ S/m after it was 1.51 × 10⁻⁶ S/m for the 1%wt. at high frequency 2 MHz. The pattern, also, depicts a typical percolation behavior; the approximate percolation thresholds are found to be at more than 4.0 wt.% of the nanocomposite content at both high and low frequencies. The rGO-MnO₂-PANA/PVA composite is believed to form a conductive path within surrounding environment when the nanofiller loading attain the conductivity threshold. However, the PVA-embedded composites with rGO-MnO₂-PANA offer an obvious elevation in electrical conductivity at nanofiller content more than 4 wt.%. This result is showing the advantage of adding the ternary nanocomposite in acting as efficient mutual site to modify the PVA conductivity. The conductivity improving may emerge due to the existence of different conduction mechanisms in the structure. One of the mechanisms is the π-π* interaction between the surface of the rGO-MnO₂ and the quinoid ring of the PANA chain. That is involved passing the electrons through sp2-bonds of the aromatic conjugation and expected electrical conductivity.^40,41 On the other hand, the magnitude of the ac conductivity increases very slowly with increasing frequency and displays a sudden jump after 1.5 MHz for all nanofiller content. This increment is attributed to the accumulation of charge carriers instructed by electron hopping mechanism.¹⁹ Thus, it is clear from Figure 10 that conductivity is the highest in the case of 5%wt rGO-MnO₂-PANA and lowest in the case of 1%wt rGO-MnO₂-PANA nanocomposites for all frequencies. These findings are in good agreement with the variation of dielectric properties of the rGO-MnO ₂ -PANA/PVA composites and the results reported previously.⁴²

Figure 10.

The electrical conductivity of the PVA composites films as a function to the nanofiller content.

Conclusion

The research was demonstrated the success of a chemical reaction to bind the poly (anthranilic acid) polymer with reduced graphene oxide and manganese dioxide nanorods to obtain ternary nanocomponents hybrid of rGO-MnO₂-PANA. The nanocompound was used as filler to embed in poly (vinyl alcohol) films and study their electrical properties in terms of permittivity and conductivity. The results indicate that the ac conductivity is initially low for all films at low frequency and then begins to increase gradually with increasing frequency. At low frequency 10 kHz the electrical conductivity value of the film with 5 wt% nanofiller was increased up to (6.01 E-04), while the conductivity of the same loaded film reaches highest value of (7.65 E-4) at frequency of 2 MHz.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Emaad T Bakir Al-Tikrity

Dhia H Hussain

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Dielectric properties of synthesized ternary hybrid nanocomposite embedded in poly (vinyl alcohol) matrix films

Abstract

Keywords

Introduction

Experimental

Materials and physical measurements

Materials

Instrumentation

Preparation of materials

Preparation of reduced graphene oxide (rGO)

Preparation of manganese dioxide (MnO2) nanorods

Synthesis of the (rGO-MnO2) nanocomposites

Synthesis of polyanthranilic acid (PANA) hollow sphere

In Situ Synthesis of rGO-MnO2-PANA

Fabrication of rGO-MnO2-PANA/PVA nanocomposite films

Dielectric constant measurements

Results and discussion

Characterization of the prepared materials

FTIR

XRD

Electron microscopy analysis The SEM/EDX

The TEM

Electrical properties

Electrical conductivity

Conclusion

Footnotes

Declaration of conflicting interests

Funding

ORCID iDs

References

Preparation of manganese dioxide (MnO₂) nanorods

In Situ Synthesis of rGO-MnO₂-PANA

Fabrication of rGO-MnO₂-PANA/PVA nanocomposite films