Journal article 847 views
Filling the gap between transient and steady shear rheology of aqueous graphene oxide dispersions
,
Benjamin V. Cunning,
Rodney S. Ruoff,
Amy Q. Shen
Rheologica Acta, Volume: 57, Issue: 4, Pages: 293 - 306
Swansea University Author:
Francesco Del Giudice
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DOI (Published version): 10.1007/s00397-018-1077-9
Abstract
Even though the rheological behavior of aqueous graphene oxide (G-O) dispersions has been shown to be strongly time-dependent, only few transient measurements have been reported in the literature. In this work, we attempt to fill the gap between transient and steady shear rheological characterizatio...
| Published in: | Rheologica Acta |
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| ISSN: | 0035-4511 1435-1528 |
| Published: |
Springer Science and Business Media LLC
2018
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa41016 |
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| Abstract: |
Even though the rheological behavior of aqueous graphene oxide (G-O) dispersions has been shown to be strongly time-dependent, only few transient measurements have been reported in the literature. In this work, we attempt to fill the gap between transient and steady shear rheological characterizations of aqueous G-O dispersions in the concentration range of 0.004 < ϕ < 3.5 wt%, by conducting comprehensive rheological measurements, including oscillatory shear flow, transient shear flow, and steady shear flow. Steady shear measurements have been performed after the evaluation of transient properties of the G-O dispersions, to assure steady-state conditions. We identify the critical concentration ϕ c = 0.08 wt% (where G-O sheets start to interact) from oscillatory shear experiments. We find that the rheology of G-O dispersions strongly depends on the G-O concentration ϕ. Transient measurements of shear viscosity and first normal stress difference suggest that G-O dispersions behave like nematic polymeric liquid crystals at ϕ/ϕ c = 25, in agreement with other work reported in the literature. G-O dispersions also display a transition from negative to positive values of the first normal stress difference with increasing shear rates. Experimental findings of aqueous graphene oxide dispersions are compared and discussed with models and experiments reported for nematic polymeric liquid crystals, laponite, and organoclay dispersions. |
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| Keywords: |
Graphene oxide, Liquid crystals, 2D suspensions, 2D dispersions, Normal stress, Rheology |
| College: |
Faculty of Science and Engineering |
| Issue: |
4 |
| Start Page: |
293 |
| End Page: |
306 |