Forced Wetting of Shear-Thinning Fluids in Confined Capillaries
Xiong Wang1, Zhenyue Yuan1, Feipeng Chen2
1Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China.
Langmuir : the ACS Journal of Surfaces and Colloids
|September 25, 2024
Summary
Shear-thinning fluids exhibit unique dynamic wetting behaviors in confined spaces. Geometric effects on the contact line create a novel equilibrium, enabling control over complex fluid wetting.
Area of Science:
- Fluid dynamics
- Interfacial phenomena
- Rheology
Background:
- Dynamic wetting in confined spaces is crucial for biological systems and microdevices.
- Shear-thinning fluids present complex interfacial behaviors due to their non-Newtonian properties.
Purpose of the Study:
- To investigate the dynamic wetting phenomenon of shear-thinning fluids in confined capillary spaces.
- To understand the influence of geometric effects and fluid properties on capillary wetting.
Main Methods:
- Utilized carboxymethyl cellulose aqueous solutions (0.5-1.5 wt %) as model shear-thinning fluids.
- Analyzed capillary wetting behavior and contact line dynamics in confined geometries.
- Investigated the relationship between viscous resistance, contact line morphology, and shear-thinning exponent.
Main Results:
- Observed a novel dynamic equilibrium distinct from Newtonian fluids due to modified viscous resistance.
- Demonstrated that contact line distortion significantly alters flow dynamics and viscous resistance.
- Found that viscous resistance is controlled by contact line morphology and shear-thinning exponent (0.7-1).
Conclusions:
- A new mechanism for dynamic wetting in confined shear-thinning fluids was identified.
- Geometric effects and rheological properties interplay to govern wetting dynamics.
- This provides a method for manipulating complex fluid wetting in microscale applications.
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