Title: Processing and characterisation of two- and three-phase polymer-based nanocomposites for energy storage applications

Authors: Emna Helal; Zoubeida Ounaies; Amira B. Meddeb

Addresses: Tunisia Polytechnic School, La Marsa 2078, Tunisia. ' Department of Mechanical and Nuclear Engineering, Pennsylvania State University, 157B Hammond Building, University Park, PA 16802, USA. ' Aerospace Engineering Department, Texas A&M University, H.R. Bright Building, Ross Street – TAMU 3141, College Station TX 77843-3141, USA

Abstract: The aim of this work is to process and characterise nanocomposites which combine the advantages of a flexible lightweight polymer matrix (polyvinylidene fluoride, PVDF), the high conductivity of single wall carbon nanotubes (SWNTs) and the attractive dielectric properties of titanium dioxide (TiO2) nanospheres, to simultaneously achieve improved dielectric constant and low dielectric loss. The effect of nanoparticles and the effect of the heat treatment on the evolution of the phase, crystallinity and dielectric behaviour of the polymer host are investigated. In particular, a transition from γ to α phase due to heat treatment is identified. In addition, the crystallinity of three-phase composites is found to decrease compared to the corresponding two-phase composites indicating a possible interaction between SWNTs and TiO2 nanofillers. Furthermore, an improvement of the permittivity is achieved in all nanocomposites at low frequencies and attributed to interfacial and orientation polarisations and to the heat treatment.

Keywords: polymer based nanocomposites; polarisation; dielectric properties; dispersion; crystallinity; polyvinylidene fluoride; PVDF; single wall carbon nanotubes; CNTs; SWNT; TiO2 nanospheres; titanium dioxide; heat treatment; energy storage; nanoparticles; nanotechnology; nanofillers.

DOI: 10.1504/IJMMP.2012.050944

International Journal of Microstructure and Materials Properties, 2012 Vol.7 No.5, pp.417 - 427

Published online: 10 Dec 2012 *

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