Functional composites from graphene-stabilised silicone emulsions

OMara, Marcus (2021) Functional composites from graphene-stabilised silicone emulsions. Doctoral thesis (PhD), University of Sussex.

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Abstract

Novel nanocomposites are emerging as promising electromechanical sensors with unparalleled sensitivities compared to traditional materials. If a percolating network of graphene can be embedded within a matrix, then system scale conductivity is conferred. The conductivity depends on a number of factors related to the morphology of the sheets and the network they form. Thus, any changes to the network brought about by mechanical stimuli such as strain will manifest as a change in conductivity. Soft polymers such as silicone elastomers undergo significant deformation even under small stress, making them ideal candidates for high sensitivity applications. Forming a percolating network of graphene in silicone is challenging due to their chemical dissimilarity. Despite this, several examples now exist of randomly distributed networks of graphene in silicone with a demonstrably high electrical response to applied strain. This work aims to extend the study of this system to templated networks of graphene in silicone by way of Pickering emulsification. The ability to structure a graphene network in this way confers additional benefits; such as a greatly reduced percolation threshold, higher conductivities at lower loadings and enhanced sensitivity. Further, we observe a robust exponential sensitivity to tensile strain, loading level-independent sensitivity and record high ∆R/R0 which facilitates the measurement of pulse and breathing (simultaneously) and high strain joint bending. This is extended to systems of lightly-interdiffused composites with potential for compressive strain or pressure sensing over an wide sensing range between 103-106 Pa, which may enable the development of electronic skin.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA0401 Materials of engineering and construction. Mechanics of materials > TA0418.9.A-Z Materials of special composition or structure, A-Z
Depositing User: Library Cataloguing
Date Deposited: 04 Nov 2021 15:22
Last Modified: 04 Nov 2021 15:22
URI: http://sro.sussex.ac.uk/id/eprint/102695

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