Colloidal Dispersions - Part 2 - Size & Shape of Colloids; Properties of Colloids - Introduction

1. UNIT-I
Colloidal dispersions
Dr. A. SUMATHI
Professor & Head
Department of Pharmaceutics
PHYSICAL PHARMACEUTICS-II
FOURTH SEMESTER B.PHARM

2. COLLOIDAL DISPERSIONS
2
▹ Classification of dispersed systems & their general
characteristics
▹ Size & shapes of colloidal particles
▹ Classification of colloids & comparative account of their general
properties
▹ Optical, kinetic & electrical properties
▹ Effect of electrolytes, coacervation, peptization & protective
action
Dr. A. SUMATHI

3. Size & shapes of colloidal particles

4. 4
Purification or
Separation of
Colloids
 Dialysis
 Ultrafiltration
 Electrodialysis
 Ultra Centrifugation
It is important since it
is slightly bigger than
coarse particles &
slightly smaller than
solutions
Dr. A. SUMATHI

5. DIALYSIS
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 This technique uses a semipermeable membrane made up of
COLLODION or CELLOPHANE, the pore size of which will prevent the
passage of colloidal particles
 It will permit small particles in the molecular or ionic range such as urea,
glucose, Sodium chloride, etc to pass through
 Dialysis is meant for purification of colloids from molecular dispersion
Dr. A. SUMATHI

6. DIALYSIS
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7. ULTRAFILTRATION
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 This technique is also used to separate &
purify colloidal material
 Filtration is conducted under negative
pressure (suction) through a dialysis
membrane supported by a buchner funnel
Dr. A. SUMATHI

8. ULTRAFILTRATION
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Dr. A. SUMATHI

9. ELECTRO DIALYSIS
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 When the contaminants contain ionic impurities, it can be removed by
the use of an electrical potential across the membrane
 Advantages – Ionic impurities are removed very quickly at faster rate
 Applications – Dialysis of Kidney
Dr. A. SUMATHI

10. ELECTRODIALYSIS
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Dr. A. SUMATHI

11. 11
Dr. A. SUMATHI

12. 12
ULTRACENTRIFUGATION
Dr. A. SUMATHI

13. Optical, Kinetic & Electrical
Properties of Colloids

14. Properties of Colloids
Optical
Properties
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15. 1. Faraday – Tyndall Effect
2. Light Scattering
Optical Properties of Colloids
Dr. A. SUMATHI

16. Properties of Colloids
Kinetic
Properties
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17. 1. Thermally induced
- Brownian movement
- Diffusion
- Osmosis
2. Gravitationally induced
- Sedimentation
3. Externally induced
- Viscosity
Kinetic Properties of Colloids
Dr. A. SUMATHI

18. Properties of Colloids
Electrical
Properties
18

19. 1. Electrophoresis
2. Electro osmosis
3. Sedimentation potential
4. Streaming potential
Electrical Properties of Colloids
Dr. A. SUMATHI

20. THANKS!
Any questions?
You can find me at drsumathi2k17@gmail.com
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Dr. A. SUMATHI
Professor & Head
Department of Pharmaceutics