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Combining Microfluidics and Microrheology to Determine Rheological Properties of Soft Matter during Repeated Phase Transitions
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Rheology modification in mixed shape colloidal dispersions. Part I: pure components
Annemieke J W Ten Brinke1, Louise Bailey2, Henk N W Lekkerkerker1
1Van't Hoff Laboratory for Physical and Colloid Chemistry, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
Soft Matter
|September 9, 2020
Summary
This study reveals how particle shape influences the rheology of colloidal dispersions, impacting their transition from gels to liquids. Understanding these flow dynamics is key for optimizing fluids in applications like drilling.
Area of Science:
- Materials Science
- Fluid Dynamics
- Colloid Science
Background:
- Colloidal dispersions are crucial in applications such as oilfield and construction-drilling fluids.
- Particle size and shape significantly affect the rheological properties of these fluids.
Purpose of the Study:
- To investigate the rheological behavior of model mineral-colloid systems with systematically varying particle shapes.
- To elucidate the underlying mechanisms governing the transition from elastoviscous gels to viscoelastic liquids in these dispersions.
Main Methods:
- Utilized a multi-technique approach including oscillatory, transient, and steady shear rheology.
- Studied model systems: plate-like gibbsite, lath-like hectorite, and rod-like boehmite aluminasols.
Main Results:
- Detailed characterization of the 'yield space' defining the transition from gel to liquid states.
- Demonstrated the significant impact of particle size and shape on rheological properties and flow behavior.
- Identified two competing flow-mediated microstructural rearrangements with distinct timescales.
Conclusions:
- A physical model explaining flow-mediated structure building and disruption was developed.
- The findings provide a baseline for understanding mixed colloid systems.
- Particle shape is a critical factor in controlling the rheology of colloidal dispersions.
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