Structure-property relations of gold and graphene nanoporous actuators

Siva Shankar Reddy Saane

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Electrochemical nanoporous actuators have low weight, large specific surface areas and low voltage operating capabilities, making them attractive for application in small-scale electromechanical devices. The actuation strain of these materials at the macroscopic scale is a manifestation of microscopic phenomena occurring at the ligament surface which is mediated by the nanoporous architecture at the mesoscopic scale.

We evaluated the actuation characteristics of ligament-resembling gold nanowires with varying cross-sectional dimensions and crystal orientations by using MSEAM, a modified surface embedded atom method. Then, we developed a multiscale modeling approach to study the performance characteristics of gold nanoporous actuators: cubic lattices, gyroids and nanoporous gold. The model features two scale transitions: (i) from the subatomic scale to the atomistic scale and (ii) from the atomic scale to the continuum scale. Finally, we studied the actuation characteristics of graphene honeycombs using atomistic calculations.

Our results provide a fundamental understanding of the physical mechanisms that couple the electrochemical injection of charge at the nanoscale to the overall actuation stroke and work output of gold and graphene nanofoams. Key mechanisms that set the nanofoams of graphene apart from that of gold are the ratio between the inherent graphene and gold stiffness, the strain-charge ratio of the graphene ribbons and gold surfaces and the different architectural morphologies that control the bending- versus stretching-dominated mechanical properties. The results can be used as guidelines for the synthesis of nanoporous actuators with optimal actuation strokes and work densities.
Originele taal-2English
KwalificatieDoctor of Philosophy
Toekennende instantie
  • Rijksuniversiteit Groningen
Begeleider(s)/adviseur
  • Onck, Patrick, Supervisor
Datum van toekenning14-sep-2015
Plaats van publicatie[Groningen]
Uitgever
Gedrukte ISBN's978-90-367-8000-1
Elektronische ISBN's978-90-367-7999-9
StatusPublished - 2015

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