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Introduction to
Colloid & Surface Chemistry
โดย รองศาสตราจารย์ เรืองศรี วัฒเนสก์
[email protected]
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CHEM 324 : Physical Chemistry IV Part II Department of Chemistry, Faculty of Science, CMU. August 2009
Content
ö The Colloidal State :
Classification & preparation
Surfactant & micellization
ö The Properties of Colloidal Dispersion
(Size & shape determination) :
Colligative properties
Kinetic properties
Optical property
ö Colloidal Stability and Its Applications
The electrical double layer
ö The gas-liquid and liquid-liquid interfaces
ö The adsorption of gas on the solid surface
ö The liquid-solid interface
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References
1. Atkins, P. W., Physical Chemistry, 8th ed., Oxford University
Press, Oxford, 2006.
2. Hiemenz, P. C. and Rajagopalan, R., Principles of Colloid
Chemistry and Surface Chemistry : Revised and Expanded,
3rd ed., Marcel Dekker, New York, 1997.
3. Hiemenz, P. C., Principles of Colloid Chemistry and Surface
Chemistry, Marcel Dekker, New York, 1977.
4. Hunter, R, J., Introduction to Modern Colloid Science,
Oxford University Press, Oxford, 1998.
5. Shaw, D. J., Colloid &Surface Chemistry, 4th ed.,
Butterworth, Oxford, 1998.
6. http://wikipedia.com and other websites
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Evaluation
• Assignment/Homework/Quiz
• Report/Presentation
• Final Exam
Total
20 points
20 points
60 points
100 points
(50%)
(Final exam : Sept 24, 2009 : 12-15 pm.)
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1. The Colloidal State
Definition :
 particle with linear dimension between
10-7 cm (10 AO) and 10-4 cm (1 )
1 - 1000 nm
 Other definitions
particle weight/ particle size etc.
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Length Scales
C-C bond
Radius of Gyration
Micelles
Vesicles
Emulsion Droplets
Latex Particles
“Colloidal Crystals”
0.1 nm
1 nm
10 nm
100 nm
1000 nm
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Homogeneous Mixtures
(True composition and properties)
Property
Particle type
True
solution
Colloid
Ions, small Large molecules,
molecules
particles
Suspension
Large particles
Particle size
0.1-1 nm
1-100 nm
100 nm and larger
Tyndall
effect
No
Yes
Yes
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Colloidal Systems
Dispersed Medium
Gas
Cont.
Medium
Gas
Liquid
Solid
NONE
Liquid Aerosol
Fog, mist
Solid Aerosol
Smoke, air
particulates
Sol
Paint,
pigmented ink,
blood
Solid Sol
Cranberry
glass, ruby
glass
Liqui
d
Foam
Whipped cream
Emulsion
Milk,
mayonnaise,
hand cream
Solid
Solid Foam
Aerogel,
styrofoam,
pumice
Gel
Gelatin, jelly,
cheese, opal
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Macromolecular
Colloids
Colloidal Dispersion
aerosols, emulsions,
sol,foam, paste
Silica gel
Basalt
Zeolite
Associated Colloids
Surfactants
“surface active agents”
Micelle formation
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CMC determinations
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Common Surfactant Classes
_
+
N Br
Cationic
cetyltrimethylammonium bromide (CTAB)
_
O
O
O Na+
S
O
Anionic
sodium dodecylsulphate (SDS)
Non-ionic
O
O
O
OH
polyethylene oxides (CiEj)
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C12E6 adsorbed at the
air-water interface in the presence of oil
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13
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Biocolloids
myoglobin
haemoglobin
Nano “golf balls”
Multiple Colloids
Megaspore wall
from a fossil of Salvinia cerebrata.
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Preparation of Colloidal Systems
Two basic methods of forming a colloid : reduction of
larger particles to colloidal size condensation of
smaller particles into colloidal particles i.e.
• spontaneous dispersion in the proper solvent
• metal evaporation in an electric arc to form a metal
vapor cools.
• solid reduction in a colloid mill.
• emulsion preparation by homogenization with the
addition of an emulsifying agent.
• Condensation of smaller particles to form a colloid
usually involves chemical reactions—typically
displacement, hydrolysis, or oxidation and reduction
• making colloidal gold, colloidal silver.
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Some areas of Science and Technology in which particles
in the colloidal size range are regularly encountered
Analytical chemistry :
adsorption indicators, ion exchange,
nephelometry, precipitate filterability,
chromatography, and decolorization
Physical chemistry :
nucleation; superheating, supercooling and
supersaturation; and liquid crystals
Biochemistry and molecular biology :
electrophoresis; osmotic and Donnan equilibria
and other membrane phenomena; viruses, nucleic
acids, and proteins; and hematology
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Chemical manufacturing :
catalysis, soaps and detergent, paints, adhesives, ink;
paper and paper coating; pigment; thickening agents;
lubricants
Environmental science :
aerosols, fog and smog, foams, water purification
and sewage treatment; cloud seeding; clean rooms
Materials science :
powder metallurgy, alloys, ceramics, cement, fibers,
and particles of all sorts
Petroleum science, geology and soil science :
oil retrieval, emulsification, soil porosity, floatation,
and ore enrichment
Household and consumer products :
milk and dairy products, beer, water proofing,
cosmetics, and encapsulated products
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Assignment -1
1. Search from Journals or websites to find
an example, in any branches of Science,
of which particles in the colloidal-size range
are encountered.
2. Write up in your own words a concise report
in A4 paper.
3. Report is due on August 21, 2009.
(10 points)
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