1. Chem 5395 J. Rusling Fall 2009 Introductory Materials “interfacial properties differ from bulk properties” Phase 1Phase 2

2. Colloidal Materials dimensions ~1 nm to 1  m nanoparticles spheres rods proteins DNA TEM of 5 nm AuNPs 2 nm

3. (A)(B) Carbon Nanotubes 0.7-2 nm diameter Single wall (SWNT)Multiwall CNT 5-40 nm diameter

4. Surfaces of nanoparticles can be derivatized AFM, AuNP on PDDA Antibodies on AuNP surface > 98% coverage of surface with AuNPs

5. Molecular aggregates can be particles or present complex interfaces: micelles and microemulsions: Oil Water O/W Bicontinuous Detergent molecule

6. 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

8. 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