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Graphene Adhesion Mechanics

Speaker: 
Narasimha Boddeti [SUTD]
Date: 
Wed, 13/11/2013 - 10:30am to 11:30am
Location: 
S13-M01-11 (Physics Conference Room)
Host: 
Navneeth Ramakrishnan
Event Type: 
Seminars

Graphene, despite being highly stiff, adheres strongly to substrates and surrounding structures with high conformity. The extent to which graphene conforms to its surrounding structures effects its thermal and electrical properties. Hence, understanding the role of adhesion is necessary for reliable and efficient design of not only graphene based nano-mechanical devices but other applications as well.

We analyzed series of experiments involving micro-cavities covered by graphene membranes adhered to the substrate along the micro-cavity edge/s. In each of these experiments, the suspended region of the graphene membrane is subjected to a pressure load through trapped pressurized gas inside the micro-cavity. Through our analysis, we describe the overall mechanics and thermodynamics of the graphene/substrate/gas system in each experiment highlighting the role played by adhesion while accounting for the non-linear mechanics of the graphene membranes.

In the first set of experiments, we determined the adhesion energy and the Young’s moduli of graphene membranes with different thicknesses with our analysis. The second set of experiments is an improvisation of the first experiment which helped us realize graphene nano-mechanical structures that can switch shape/size via pressure load and adhesion. An extended analysis is developed to completely describe the mechanics. The third set using the same structures as in the second experiment lead us to pull-in of graphene membranes under the influence of surface interactions between graphene and the substrate. This pull-in behavior is captured by our analytical model and made use of to determine the magnitude of the interactions.

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