Abstract
The mechanical properties of graphene oxide (GO) paper are critically defined both by the mechanical properties of the constituent GO sheets and the interaction between these sheets. Functional carbonyl and carboxyl groups decorating defects, expected to be predominantly sheet edges of the GO, are shown to transfer forces to the in-plane carbon-carbon bonding using a novel technique combining atomic force microscopy (AFM) to mechanically deform discrete volumes of GO materials while synchrotron Fourier-transform infra-red (FTIR) microspectroscopy evaluated molecular level bond deformation mechanisms of the GO. Spectroscopic absorption peaks corresponding to in-plane aromatic C=C bonds from GO sheets were observed to shift during tensile tests. Importantly, FTIR provided information on clear absorption peak shifts from C=O bonds linking along the GO sheet edges, indicating transfer of forces between both C=C and C=O bonds during tensile deformation. Grüneisen parameters were used to quantitatively link the macroscopic FTIR peak shifts to molecular level chemical bond strains, with relatively low bond strains prevalent when applying external forces to the GO paper suggesting probing of hydrogen bonding interactions. We propose a mechanistic description of molecular interactions between GO sheets in the paper from these experiments, which is important in future strategies for further modification and improvement of GO-based materials.
Highlights
Graphene oxide (GO) is an increasingly important material used for scalable, cost-effective routes to fabricate graphene devices[1,2,3] and is typically produced by solution-based chemical modification of graphite[4,5,6]
This work applied strategies previously developed for determining specific component mechanics in multi-phase systems, including individual nanofibers in bone[22] and simple composite volumes in mineralized tissues[23], and is considered advantageous for understanding inherent GO paper behavior as relatively small samples prepared using focused ion beam (FIB) are devoid of large defects present when testing at the macroscale
Mechanical deformation was applied to the FIB-fabricated micro-beams using atomic force microscopy (AFM)
Summary
This is an Accepted Manuscript, which has been through the Royal Society of Chemistry peer review process and has been accepted for publication. Accepted Manuscripts are published online shortly after acceptance, before technical editing, formatting and proof reading. Using this free service, authors can make their results available to the community, in citable form, before we publish the edited article. Authors can make their results available to the community, in citable form, before we publish the edited article We will replace this Accepted Manuscript with the edited and formatted Advance Article as soon as it is available. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains
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