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Chem 5395 J. Rusling. “interfacial properties differ from bulk properties”. Fall 2009 Introductory Materials. Phase 1. Phase 2. Colloidal Materials dimensions ~1 nm to 1 m. spheres. nanoparticles. proteins. rods. DNA. 2 nm. TEM of 5 nm AuNPs. (A). (B). Carbon Nanotubes.
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Chem 5395J. Rusling “interfacial properties differ from bulk properties” Fall 2009 Introductory Materials Phase 1 Phase 2
Colloidal Materials dimensions ~1 nm to 1 m spheres nanoparticles proteins rods DNA 2 nm TEM of 5 nm AuNPs
(A) (B) Carbon Nanotubes Multiwall CNT Single wall (SWNT) 0.7-2 nm diameter 5-40 nm diameter
Surfaces of nanoparticles can be derivatized Antibodies on AuNP surface AFM, AuNP on PDDA > 98% coverage of surface with AuNPs
Water Water Oil Water Water Molecular aggregates can be particles or present complex interfaces: micelles and microemulsions: O/W Bicontinuous Detergent molecule
Many practical applications of colloids/nanoparticles: • sensors, chromatography, electrophoresis • membranes, catalysis, water treatment, detergency, ceramics • adhesion, aerosols, smog, oil recovery • soaps, drugs, paints, lubricants, beer Common Factors:small particles - high surf. Area large molecules - polymers, proteins, DNA Size range between m and approaching atomic scale
Colloids are classed as: Lyophobic “solvent fearing” in water, hydrophobic Lyophilic “solvent loving” in water, hydrophilic Colloidal suspension (dispersion) has continuous (solvent) And dispersed (particulate) phases Lyophilic dispersions - usually true solutions, e.g. polymer protein solution Lyophobic dispersion - 2 or more phases, see examples