1. BCAT-5 Three-Phase Dynamics
Simon Fraser University
Art Bailey, Barbara Frisken, Juan Sabin

2. Three-phase Separation Dynamics
One sentence definition of SFU’s BCAT-5 Experiment
The study of phase separation dynamics when gas, solid and liquid phases of a colloidal suspension coexist.

3. Outline States of Matter / Phase Transitions Colloids
States of Colloidal Matter
Colloid Experiments in Space
BCAT-5

4. “Traditional” States of Matter

5. Differences between states

6. Atomic Differences

7. Phase Transitions
Transition from one state to another
Boiling
Freezing
Sublimation
Demixing
Mixtures
Alloys
Polymer blends
What are the “mechanisms” of these phase transitions?
Tougher problems to study because non-equilibrium problems.

8. Phase Transitions that Matter
Vinaigrette
Metal / Plastic Alloys
Fuels

9. Phase Separation in 3-Phase Coexistence
2-phase Separation studied for more than 50 years.
3-phase Separation
Crystals, Liquid and Gas all forming out of a homogenized mixture
Applications
Properties of polyolefin blended plastics
Mechanical properties determined by the separation / crystallization.
Polypropylene and Polyethylene
Fire retardants, packing materials
Protein Crystallization
Tetragonal Lyzozyme crystals
lysozyme.co.uk/crystallization.php

10. What’s a Colloid?
Colloids – Particles of size 1 nm – 10 microns. Larger than atomic/molecular size, smaller than ‘macroscopic’.

11. Why Colloids? Lots of technological examples
Colloids model atomic and molecular systems but are simpler to study

12. Hard Sphere Colloids
PMMA colloid with PHSA coating

13. Phases of Colloids
Hard Spheres – like billiard balls

14. Colloid-Polymer Mixtures
Depletion Attration – Entropy causes an “effective” attractive interaction.

15. Polymers Increase Phase Behaviour
PCS
BCAT-3,4-CP
BCAT-5 Experiments
3 Samples in 3-phase region.

16. Looking Forward
W.C.K. Poon

17. Colloids in Space
PHaSE
CDOT
CDOT-2
PCS
Coexistence
Fully Crystalline

18. Why Colloids in Space Sedimentation
Particle a h
Ball bearing
1 mm
10-20 m
Air molecule
1 nm
103 m
Polystyrene spheres in water
2 mm
particle size, a
gravitational height, h
if h<a,gravity is important
Gravity causes colloids to fall to the bottom of the sample cell!

19. Colloid-Polymer Phase Separation

20. BCAT-5 Sample Tray
The BCAT-5 Slow Growth Sample Module is 12.7cm x 26.7cm x 3.2cm and contains 10 (2.3cc) sample cuvettes.

21. BCAT-5 Apparatus

22. Phase Separation (BCAT-3)
Colloid rich phase
Colloid poor phase
Measure the size of the regions to determine the rate of phase growth.
Courtesy of D.Weitz, P. Lu, Harvard University

23. SFU on BCAT-5

24. Looking Forward
W.C.K. Poon

25. The End
Questions?

26. Soft Matter Physics
“Particles” interact with energies comparable to thermal energies.
Entropy
Coulombic forces (ie. Charge)
No (well…. At least not much) quantum mechanics.

27. Interesting Properties
Gels
Shear thinning or shear thickening

28. “Soft” Matter