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Rheology modification in mixed shape colloidal dispersions. Part II: mixtures
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 10, 2020
Summary
Adding different shaped colloidal particles to hectorite clay significantly enhances dispersion properties. Spherical particles caused the largest increase in viscosity and yield stress, demonstrating shape-dependent rheological improvements in mixed colloid systems.
Area of Science:
- Colloid and Surface Science
- Materials Science
- Rheology
Background:
- Understanding mixed colloid systems is crucial for optimizing industrial fluids.
- The rheological properties of dispersions are highly sensitive to particle shape and concentration.
Purpose of the Study:
- To investigate the impact of varying colloidal particle shapes on the rheological behavior of hectorite clay dispersions.
- To quantify the enhancements in rheological properties due to the addition of minor components with different particle morphologies.
Main Methods:
- Systematic variation of aluminasol particle shapes (rod, platelet, sphere) added to hectorite clay dispersions.
- Measurement of oscillatory, transient (creep), and steady shear flow rheological properties.
- Analysis of the relationship between particle shape and enhanced dispersion characteristics.
Main Results:
- Addition of 0.25 wt% minor component dramatically enhanced rheological properties.
- Enhancements increased in the order: rods < platelets < spheres.
- Shear moduli, low-stress viscosities, and yield stresses increased significantly, with spheres showing up to 500x enhancement.
Conclusions:
- Particle shape is a critical factor in controlling the rheology of mixed colloid systems.
- The study provides a quantitative baseline for optimizing mixed dispersions for industrial applications like oilwell-drilling fluids.
- Future work could focus on developing complete models for these complex systems.
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