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Monodisperse colloidal plates under shear
1Semiconductor Physics, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE, United Kingdom.
Summary
Shear flow induces distinct structural changes in colloidal particle dispersions, transitioning between columnar and layered phases. These shear-induced structures relax to the equilibrium columnar phase over time.
Area of Science:
- Colloid science
- Rheology
- Materials science
Background:
- Colloidal dispersions exhibit complex structures at rest.
- Understanding shear-induced behavior is crucial for material processing.
Purpose of the Study:
- Investigate structural transitions in plate-shaped colloidal particles under shear.
- Characterize shear-induced phases and their relaxation dynamics.
Main Methods:
- Rheological measurements
- Structural analysis of colloidal dispersions under shear
- Microscopy techniques
Main Results:
- At low shear rates, columnar structures align with flow.
- High shear rates induce a layered phase with normals in the gradient direction.
- Evidence of shear-induced phase separation and disorder at intermediate/high rates.
- Shear-induced structures relax to the equilibrium columnar phase over hours.
Conclusions:
- Shear flow significantly alters colloidal dispersion structures.
- Distinct shear-induced phases exist, with transitions influenced by shear rate.
- Relaxation dynamics involve structural rearrangements and changes in orientational order.
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