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Introduction to Colloidal systems

Introduction to Colloidal systems. Joachim Koetz, Universität Potsdam. Alchemist. Elexier of life ? potable gold-solution (aurum potabile). Definition ( Graham ). Colloids are glue-like substances, diffuse very slowly, and do not dialyse. Types of disperse systems

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Introduction to Colloidal systems

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  1. Introduction to Colloidal systems Joachim Koetz, Universität Potsdam

  2. Alchemist • Elexier of life ? • potable gold-solution (aurum potabile)

  3. Definition (Graham) • Colloids are glue-like substances, diffuse very slowly, and do not dialyse

  4. Types of disperse systems (W. Ostwald) Disperse systems solutions < 1 nm colloidal dispersions 1 bis 1000 nm suspensions > 1000 nm

  5. Definition Any particle that has some linear dimension between 1 nm and 1 μm is considered a colloid! However, the limits are rather arbitrary.

  6. Definition: • A state of subdivision in which the particles, droplets, or bubbles dispersed in another phase have at least one dimension between • 1 – 1000 nm • All combinations are possible between gas, liquid, and solid • W. Ostwald

  7. History of Colloid Chemistry • 1927 Burry, Ekwall: Associating Colloids • 1929 Staudinger: Macromolecules

  8. Associating Colloids • Amphiphilic self-organizing systems • Colloids are associated physically, not chemically • Size and shape of the associates can change

  9. Macromolecules as colloidal systems • Any macromolecule consisting of 103 up to 109 atoms • Any dispersed macromolecular coil having colloidal dimensions

  10. History of Colloid Chemistry • 1923 Svedberg: Ultracentrifugation • 1932 Ruska: Electron Microscopy

  11. The Colloidal Domain • One dimension between 1 and 1000 nm • All combinations of dispersed matter • Classification: - colloidal dispersions - associating colloids - macromolecules

  12. Biomineralization

  13. Nanoparticles as Quantendots • Color effects in glases (e.g. CdS or gold) • Non linear optical effects (fast optoelectronical switches) • High storage capacity (optical storage)

  14. Formation of Nanoparticles(Nanotechnology) • Particle formation from gas phases • Particle formation from droplets • Particle formation from Sol-Gel-Processes

  15. Nanoparticles produced by nucleation processes • Colloidal Sulfur • Colloidal Gold • Latex Particles • Nanocrystallites

  16. Conditions for the production of monodisperse nanoparticles- Heterogeneous nucleation- La Mer diagram

  17. Analytical chemistry Physical chemistry Biochemistry Material Science Petroleum Science Household products Imaging technology Adsorption phenomena, chromatography Nucleation, supersaturation, liquid crystals Electrophoresis, osmosis, ultrafiltration Ceramics, fibres, powder metallurgy Oil recovery, Milk, beer, cosmetics Emulsions, printing inks, paper coating Disciplines and Topics for which Colloids and colloidal phenomena are important

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