Flow-induced ordering of particles and flow velocity profile transition in a tube flow of graphene oxide dispersions |
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Authors: | Seung-Ho Hong Tian-Zi Shen |
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Affiliation: | 1. School of Electronic &2. Electrical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do, Republic of Korea |
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Abstract: | We measured the S- and P-order parameters of flow-induced ordered graphene oxide (GO) particles and the flow velocity profiles for a flowing aqueous GO dispersion in a tube, by using an optical method. The order parameters clearly exhibit increasing concentric biaxial ordering as the flow velocity increases, with the exception of a disordered centre. Newtonian to non-Newtonian transition in the flow velocity profile is found, changing from a parabolic shape to a fuller shape at very low Reynolds numbers less than 10. This is attributed to the shear thinning effect (i.e., an ordering-induced reduction in viscosity). In the Newtonian flow, a uniaxial ordering was dominant; whereas a biaxial ordering sharply increased in the non-Newtonian flow, indicating that both the ordering of GO particles and the interparticle interactions influence the flow profile transition. |
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Keywords: | graphene oxide dispersion flow-induced ordering lyotropic |
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