Wetting kinetics of polymer solutions and force‐based contact angles |
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| Authors: | Amer Al‐Shareef P Neogi Baojun Bai |
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| Affiliation: | 1. Dept. of Chemical and Biochemical Engineering, Missouri University of Science and Technology, Rolla, MO;2. Dept. of Geological Science and Engineering, Missouri University of Science and Technology, Rolla, MO |
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| Abstract: | The effect of the shear thinning behavior and elasticity of polymer solutions on the dynamic contact angles are investigated. Under dynamic conditions, the contact angle of a liquid on a solid surface changes significantly with the substrate velocity from its equilibrium value. The dynamic contact angles for polyethylene oxide (PEO) solutions of two molecular weights 3 × 105 and 4 × 106 have been measured using a polyethylene terephthalate (PET) plate. The three‐parameter Ellis model to fit the rheological data to obtain shear thinning power n, characteristic shear stress, and the zero‐shear viscosity is used. The theory indicates that dynamic contact angles follow power law in this instance instead of showing Newtonian behavior with zero‐shear viscosity when the shear thinning effects are considered. The elastic effect becomes important at larger polymer concentrations that reduces the dependence on capillary number, that is, reduces n keeping with the experiments. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2533–2541, 2016 |
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| Keywords: | surface chemistry/physics transport rheology |
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