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โดย รองศาสตราจารย์ เรืองศรี วัฒเนสก์ ruangsri@gmail

I ntroduction to C olloid & S urface C hemistry. โดย รองศาสตราจารย์ เรืองศรี วัฒเนสก์ ruangsri@gmail.com. CHEM 324 : Physical Chemistry IV Part II Department of Chemistry, Faculty of Science, CMU. August 2009. C ontent. The Colloidal State : Classification & preparation

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โดย รองศาสตราจารย์ เรืองศรี วัฒเนสก์ ruangsri@gmail

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  1. Introduction toColloid & Surface Chemistry โดย รองศาสตราจารย์ เรืองศรี วัฒเนสก์ ruangsri@gmail.com CHEM 324 : Physical Chemistry IV Part II Department of Chemistry, Faculty of Science, CMU. August 2009

  2. Content The Colloidal State : Classification & preparation Surfactant & micellization The Properties of Colloidal Dispersion (Size & shape determination) : Colligative properties Kinetic properties Optical property Colloidal Stability and Its Applications The electrical double layer The gas-liquid and liquid-liquid interfaces The adsorption of gas on the solid surface The liquid-solid interface

  3. References Atkins, P. W., Physical Chemistry,8th ed., Oxford University Press, Oxford, 2006. Hiemenz, P. C. and Rajagopalan, R., Principles of Colloid Chemistry and Surface Chemistry : Revised and Expanded, 3rd ed., Marcel Dekker, New York, 1997. Hiemenz, P. C., Principles of Colloid Chemistry and Surface Chemistry, Marcel Dekker, New York, 1977. Hunter, R, J., Introduction to Modern Colloid Science, Oxford University Press, Oxford, 1998. Shaw, D. J., Colloid&Surface Chemistry, 4thed., Butterworth, Oxford, 1998. http://wikipedia.com and other websites

  4. Evaluation Assignment/Homework/Quiz 20 points Report/Presentation 20 points Final Exam 60 points Total 100 points (50%) (Final exam : Sept 24, 2009 : 12-15 pm.)

  5. 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.

  6. Length Scales C-C bond 0.1 nm Radius of Gyration 1 nm Micelles 10 nm Vesicles Emulsion Droplets 100 nm Latex Particles “Colloidal Crystals” 1000 nm

  7. Homogeneous Mixtures (True composition and properties)

  8. Colloidal Systems

  9. Macromolecular Colloids Colloidal Dispersion aerosols,emulsions,sol,foam, paste Surfactants “surface active agents” Silica gel Zeolite Basalt Associated Colloids Micelle formation

  10. CMC determinations

  11. Common Surfactant Classes

  12. C12E6 adsorbed at the air-water interface in the presence of oil

  13. Megaspore wall from a fossil of Salvinia cerebrata. Biocolloids Nano “golf balls” Multiple Colloids haemoglobin myoglobin

  14. 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.

  15. 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

  16. 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

  17. Assignment -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. • Write up in your own words a concise report • in A4 paper. • Report is due on August 21, 2009. • (10 points)

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