title: 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.
authors.affiliation: Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK.
authors.forename: Nadeesh
authors.initials: N
authors.lastname: Madusanka
authors.forename: Sai G
authors.initials: SG
authors.lastname: Shivareddy
authors.forename: Pritesh
authors.initials: P
authors.lastname: Hiralal
authors.forename: Mark D
authors.initials: MD
authors.lastname: Eddleston
authors.forename: Youngjin
authors.initials: Y
authors.lastname: Choi
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Oliver
authors.forename: Gehan A J
authors.initials: GA
authors.lastname: Amaratunga