Dielectric behaviour of plasma hydrogenated TiO2/cyanoethylated cellulose nanocomposites.


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Authors
Adassooriya, Nadeesh M  ORCID logo  https://orcid.org/0000-0002-1174-5388
Ozgit, Dilek 
Shivareddy, Sai G 
Hiralal, Pritesh 
Dahanayake, Damayanthi 
Abstract

The interface between the polymer and nanoparticle has a vital role in determining the overall dielectric properties of a dielectric polymer nanocomposite. In this study, a novel dielectric nanocomposite containing a high permittivity polymer, cyanoethylated cellulose (CRS) and TiO2 nanoparticles surface modified by hydrogen plasma treatments was successfully prepared with different weight percentages (10%, 20% and 30%) of hydrogenated TiO2. Internal structure of H plasma treated TiO2 nanoparticles (H-TiO2) and the intermolecular interactions and morphology within the polymer nanocomposites were analysed. H-TiO2/CRS thin films on SiO2/Si wafers were used to form metal-insulator-metal (MIM) type capacitors. Capacitances and loss factors in the frequency range of 1 kHz to 1 MHz were measured. At 1 kHz H-TiO2/CRS nanocomposites exhibited ultra-high dielectric constants of 80, 118 and 131 for nanocomposites with 10%, 20% and 30% weight of hydrogenated TiO2 respectively, significantly higher than values of pure CRS (21) and TiO2 (41). Furthermore, all three H-TiO2 /CRS nanocomposites show a loss factor <0.3 at 1 kHz and low leakage current densities (10-6 A cm-2-10-7 A cm-2). Leakage was studied using conductive atomic force microscopy (C-AFM) and it was observed that the leakage is associated with H-TiO2 nanoparticles embedded in the CRS polymer matrix. Although, modified interface slightly reduces energy densities compared to pristine TiO2/CRS system, the capacitance values for H-TiO2/CRS-in the voltage range of -2 V to 2 V are very stable. Whilst H-TiO2/CRS possesses ultra-high dielectric constants (>100), this study reveals that the polymer nanoparticle interface has a potential influence on dielectric behaviour of the composite.

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Acknowledgements: This work was supported by Dyson Research Ltd. NA is also grateful to the Cambridge Commonwealth Trust for financial support and Prof. William Jones, Department of Chemistry, University of Cambridge for providing wet chemical laboratory facilities. Sri Lanka Institute of Nanotechnology (SLINTEC) is acknowledged for providing TEM and solid-state NMR facilities. NA further acknowledges Dr Nuwan de Silva and Dr Dinara Gunasekera for ss-NMR data collection.

Keywords
40 Engineering, 4016 Materials Engineering, 34 Chemical Sciences, 4018 Nanotechnology, Nanotechnology, Bioengineering, 7 Affordable and Clean Energy
Journal Title
Nanoscale
Conference Name
Journal ISSN
2040-3364
2040-3372
Volume Title
Publisher
Royal Society of Chemistry (RSC)
Sponsorship
Engineering and Physical Sciences Research Council (EP/P024947/1)
Engineering and Physical Sciences Research Council (EP/S019367/1)
Engineering and Physical Sciences Research Council (EP/R00661X/1)