Abstract
The rheological behaviour of concentrated aqueous dispersions of graphene oxide (GO) was studied as a model system and then compared to those of GO in poly(methyl methacrylate) (PMMA). Dynamic and steady shear tests were conducted using a parallel plate rheometer. The aqueous system behaved as a reversibly flocculated dispersion with linear viscoelastic regions (LVR) extending up to strains of 10 %. Dynamic frequency sweeps conducted within the LVR showed a classic strong-gel spectrum for high concentrations. Under steady shear, the dispersions shear-thinned up to a Peclet number (Pe) <1, followed by a power law at higher Pe. The dispersions were thixotropic and recovered their structure after 60 min rest. The change in rheological properties of the PMMA upon the addition of the GO was less pronounced possibly due to the absence of hydrogen bonding; a relatively small increase in viscosity was found, which is encouraging for the melt processing of graphene composites.
Highlights
Graphene has attracted significant interest since it was first isolated in 2004 [1,2,3] due to its extraordinary physical properties [4, 5] which make it ideal for a wide range of applications including sensors, batteries, supercapacitors, hydrogen storage and composites [6,7,8,9,10]
The change in rheological properties of the poly(methyl methacrylate) (PMMA) upon the addition of the graphene oxide (GO) was less pronounced possibly due to the absence of hydrogen bonding; a relatively small increase in viscosity was found, which is encouraging for the melt processing of graphene composites
Aqueous dispersions Dynamic shear properties The dispersions of GO sheets showed linear viscoelastic behaviour under dynamic shear up to a critical strain of between 0.1 and 10 % depending on the concentration, with G0 higher than G00 (Fig. 1)
Summary
Graphene has attracted significant interest since it was first isolated in 2004 [1,2,3] due to its extraordinary physical properties [4, 5] which make it ideal for a wide range of applications including sensors, batteries, supercapacitors, hydrogen storage and composites [6,7,8,9,10]. Results and discussion Aqueous dispersions Dynamic shear properties The dispersions of GO sheets showed linear viscoelastic behaviour under dynamic shear up to a critical strain of between 0.1 and 10 % depending on the concentration, with G0 higher than G00 (Fig. 1).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
