Nanocomposites of TiO₂/cyanoethylated cellulose with ultra high dielectric constants

Abstract

A novel dielectric nanocomposite containing a high permittivity polymer, cyanoethylated cellulose (CRS) and TiO2 nanoparticles was successfully prepared with different weight percentages (10%, 20% and 30%) of TiO2. The intermolecular interactions and morphology within the polymer nanocomposites were analysed. TiO2/CRS nanofilms on SiO2/Si wafers were used to form metal-insulator-metal type capacitors. Capacitances and loss factors in the frequency range of 1 kHz-1 MHz were measured. At 1 kHz CRS-TiO2 nanocomposites exhibited ultra high dielectric constants of 118, 176 and 207 for nanocomposites with 10%, 20% and 30% weight of TiO2 respectively, significantly higher than reported values of pure CRS (21), TiO2 (41) and other dielectric polymer-TiO2 nanocomposite films. Furthermore, all three CRS-TiO2 nanocomposites show a loss factor <0.3 at 1 kHz and low leakage current densities (10(-6)-10(-7) A cm(-2)). Leakage was studied using conductive atomic force microscopy and it was observed that the leakage is associated with TiO2 nanoparticles embedded in the CRS polymer matrix. A new class of ultra high dielectric constant hybrids using nanoscale inorganic dielectrics dispersed in a high permittivity polymer suitable for energy management applications is reported.

Effect of nano filler concentration on leakage current and partial discharge properties of zepoxy nano composites

“…The minimum value of LC occurs on 0.4% filler loading. This pattern of increasing LC with the increase in TiO 2 concentration has been also reported by Madusanka et al [31].…”

Enhanced dielectric thermal stability and permittivity of flexible composite films based on BaTiO3 nanoparticles highly filled PVDF/PAN blend nanofibrous membranes

“…For polymer/ceramic filler composites, the improved dielectric permittivity is mainly ascribed to the interfacial polarization, also known as the Maxwell-Wagner effect [23][24][25]. In this work, for DCFs-Filtering, the enhancement of dielectric permittivity is attributed to high loading of BaTiO 3 nanoparticles and in particular remarkable interfacial polarization from good dispersion.…”

Polymer-Based Gate Dielectrics for Organic Field-Effect Transistors

“…Additionally, an additional PVP capping layer with a thickness below 50 nm suppressed leakage current to below 10 −7 A cm −2 at ±3 V without a significant loss of capacitance. 230 Amaratunga et al 231 reported cyanoethylated cellulose-based dielectric nanocomposites with ultrahigh dielectric constants exceeding 100 with TiO 2 NP loadings of 10% to 30%. The high dielectric constants, which exceed both the embedded nanofillers (TiO 2 ) and the polymer matrix, were attributed to the specific HOMO−LUMO energy alignments between TiO 2 and the cyanoethylated cellulose.…”