Gold-Nanoparticle-Deposited TiO2 Nanorod/Poly(Vinylidene Fluoride) Composites with Enhanced Dielectric Performance.

Pornsawan Kum-Onsa,Viyada Harnchana,Prinya Chindaprasirt,Nutthakritta Phromviyo,Narong Chanlek,Jedsada Manyam,Prasit Thongbai

doi:10.3390/polym13132064

Abstract

Flexible dielectric polymer composites have been of great interest as embedded capacitor materials in the electronic industry. However, a polymer composite has a low relative dielectric permittivity (ε′ < 100), while its dielectric loss tangent is generally large (tanδ > 0.1). In this study, we fabricate a novel, high-permittivity polymer nanocomposite system with a low tanδ. The nanocomposite system comprises poly(vinylidene fluoride) (PVDF) co-filled with Au nanoparticles and semiconducting TiO2 nanorods (TNRs) that contain Ti3+ ions. To homogeneously disperse the conductive Au phase, the TNR surface was decorated with Au-NPs ~10–20 nm in size (Au-TNRs) using a modified Turkevich method. The polar β-PVDF phase was enhanced by the incorporation of the Au nanoparticles, partially contributing to the enhanced ε′ value. The introduction of the Au-TNRs in the PVDF matrix provided three-phase Au-TNR/PVDF nanocomposites with excellent dielectric properties (i.e., high ε′ ≈ 157 and low tanδ ≈ 0.05 at 1.8 vol% of Au and 47.4 vol% of TNRs). The ε′ of the three-phase Au-TNR/PVDF composite is ~2.4-times higher than that of the two-phase TNR/PVDF composite, clearly highlighting the primary contribution of the Au nanoparticles at similar filler loadings. The volume fraction dependence of ε′ is in close agreement with the effective medium percolation theory model. The significant enhancement in ε′ was primarily caused by interfacial polarization at the PVDF–conducting Au nanoparticle and PVDF–semiconducting TNR interfaces, as well as by the induced β-PVDF phase. A low tanδ was achieved due to the inhibited conducting pathway formed by direct Au nanoparticle contact.

Highlights

With recent developments in the electronic industry, dielectric polymer composite materials have attracted increasing interest for a wide range of applications, such as energy storage devices, dielectric capacitors, and electromechanical actuators [1,2].Poly(vinylidene fluoride) (PVDF) has been used as a dielectric polymer material due to its high energy density, high electric break down field, and flexibility [3,4]
Au nanoparticles are spherical with diameters of TiO2 nanorods (TNRs) hybrid nanoparticles
This study presented a novel method for successfully achieving high ε′ and low tanδ in three-phase poly(vinylidene fluoride) (PVDF) polymer-matrix nanocomposites

Summary

Introduction

With recent developments in the electronic industry, dielectric polymer composite materials have attracted increasing interest for a wide range of applications, such as energy storage devices, dielectric capacitors, and electromechanical actuators [1,2].Poly(vinylidene fluoride) (PVDF) has been used as a dielectric polymer material due to its high energy density, high electric break down field, and flexibility [3,4]. Many studies have attempted to fabricate polymer composites with high ε0 values by incorporating fillers into the PVDF matrix. Several ceramic/polymer composites, such as CaCu3 Ti4 O12 /PVDF [5,12], CaCu3 Ti4 O12 /polystyrene [13], BaTiO3 /PVDF [6], Ba0.5 Sr0.5 TiO3 /P(VDF-CTFE) [14], and Ba0.6 Sr0.4 TiO3 /PVDF [15], have high ε0 values (~50–80 at 1 kHz). Metal/polymer composites, such as Ni/PVDF, Ni/P(VDF-CTFE) [17,18], MWCNT/PVDF [8,19], and Ag/PVDF [7,20], can exhibit significantly higher ε0 at low concentrations of conducting fillers than ceramic/PVDF composites

Objectives

Discussion

Conclusion