TY - JOUR

T1 - Surface and interfacial interactions of multilayer graphitic structures with local environment

AU - Mazzocco, Riccardo

AU - Robinson, Benjamin

AU - Rabot, Caroline

AU - Delamoreanu, A.

AU - Zenasni, Aziz

AU - Dickinson, James

AU - Boxall, Colin

AU - Kolosov, Oleg

PY - 2015/6/30

Y1 - 2015/6/30

N2 - In order to exploit the potential of graphene in next-generation devices, such as supercapacitors, rechargeable batteries, displays and ultrathin sensors, it is crucial to understand the solvent interactions with the graphene surface and interlayers, especially where the latter may be in competition with the former, in the medium of application deployment. In this report, we combine quartz crystal microbalance (QCM) and ultrasonic force microscopy methods to investigate the changes in the film-substrate and film-environment interfaces of graphene and graphene oxide films, produced by diverse scalable routes, in both polar (deionised water) and non-polar (dodecane) liquid and vapour environments. In polar liquid environments, we observe nanobubble adsorption/desorption on the graphene film corresponding to a surface coverage of up to 20%. As no comparable behaviour is observed for non-polar environment, we conclude that nanobubble formation is directly due to the hydrophobic nature of graphene with direct consequences for electrode structures immersed in electrolyte solutions. The amount of water adsorbed by the graphene films was found to vary considerably from 0.012 monolayers of water per monolayer of reduced graphene oxide to 0.231 monolayers of water per monolayer of carbon diffusion growth graphene. This is supported by direct nanomechanical mapping of the films immersed in water where an increased variation of local stiffness suggests water propagation within the film and/or between the film and substrate. Film thickness calculations performed for QCM, atomic force microscopy topography, Raman spectroscopy and optical transmission measurements, show that due to the turbostratic structures of large area films Raman returns results an order of magnitude lower (1-2 graphene layers) than direct measurement by QCM (46 ± 1 layers).

AB - In order to exploit the potential of graphene in next-generation devices, such as supercapacitors, rechargeable batteries, displays and ultrathin sensors, it is crucial to understand the solvent interactions with the graphene surface and interlayers, especially where the latter may be in competition with the former, in the medium of application deployment. In this report, we combine quartz crystal microbalance (QCM) and ultrasonic force microscopy methods to investigate the changes in the film-substrate and film-environment interfaces of graphene and graphene oxide films, produced by diverse scalable routes, in both polar (deionised water) and non-polar (dodecane) liquid and vapour environments. In polar liquid environments, we observe nanobubble adsorption/desorption on the graphene film corresponding to a surface coverage of up to 20%. As no comparable behaviour is observed for non-polar environment, we conclude that nanobubble formation is directly due to the hydrophobic nature of graphene with direct consequences for electrode structures immersed in electrolyte solutions. The amount of water adsorbed by the graphene films was found to vary considerably from 0.012 monolayers of water per monolayer of reduced graphene oxide to 0.231 monolayers of water per monolayer of carbon diffusion growth graphene. This is supported by direct nanomechanical mapping of the films immersed in water where an increased variation of local stiffness suggests water propagation within the film and/or between the film and substrate. Film thickness calculations performed for QCM, atomic force microscopy topography, Raman spectroscopy and optical transmission measurements, show that due to the turbostratic structures of large area films Raman returns results an order of magnitude lower (1-2 graphene layers) than direct measurement by QCM (46 ± 1 layers).

KW - Graphene

KW - thickness measurement

KW - segregation

KW - chemical reduction

KW - Atomic Force Microscopy

KW - Ultrasonic Force Microscopy

U2 - 10.1016/j.tsf.2015.04.016

DO - 10.1016/j.tsf.2015.04.016

M3 - Journal article

VL - 585

SP - 31

EP - 39

JO - Thin Solid Films

JF - Thin Solid Films

SN - 0040-6090

ER -