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Nanomechanical characterization of SU8/ZnO nanocomposite films for applications in energy-harvesting microsystems

Krishna, B and Chaturvedi, A and Mishra, N and Das, K (2018) Nanomechanical characterization of SU8/ZnO nanocomposite films for applications in energy-harvesting microsystems. In: JOURNAL OF MICROMECHANICS AND MICROENGINEERING, 28 (11).

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Official URL: http://dx.doi.org/10.1088/1361-6439/aae10c

Abstract

Integration of piezoelectric zinc oxide (ZnO) nanoparticles with SU8 in the form of photopatternable nanocomposite films can lead to the development of a new generation of energy-harvesting microdevices. Design of such energy-harvesting micro/nano-systems will require knowledge of the mechanical properties of the SU8/ZnO nanocomposite thin films for various loadings of ZnO. This work presents characterization of mechanical properties of SU8/ZnO nanocomposite films with ZnO concentration varying in the range of 0-25 wt% via quasi-static and dynamic nanoindentation. These films were fabricated using conventional microfabrication steps involving dispersion of ZnO in SU8 by ultrasonication, followed by spin-coating and UV exposure. The elastic modulus obtained via quasi-static nanoindentation varies from similar to 6.2 GPa for pristine SU8 to similar to 8.8 GPa for SU8/25 wt% ZnO nanocomposite, while hardness varies from 402 MPa to similar to 520 MPa for SU8/ZnO nanocomposites in the same range of ZnO wt%. The experimentally-obtained elastic modulus has also been compared with estimates obtained via Eshelby-Mori-Tanaka micromechanics. Storage modulus, loss modulus and loss factor obtained via dynamic nanoindentation tests indicate that the SU8/ZnO nanocomposites exhibit viscoelastic behavior in the studied frequency-range of 10 Hz to 201.5 Hz. Microstructural characterization via scanning electron microscopy and optical characterization via UV-vis spectrometry of the nanocomposites have also been reported.

Item Type: Journal Article
Additional Information: Copy right for this article belong to IOP PUBLISHING LTD
Keywords: nanocomposites; microfabrication; dynamic nanoindentation; viscoelastic properties
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Depositing User: Id for Latest eprints
Date Deposited: 22 Oct 2018 15:03
Last Modified: 22 Oct 2018 15:03
URI: http://eprints.iisc.ac.in/id/eprint/60927

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