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Macro Micro Nano

Macro Micro Nano. Micro Red blood cells. Macro Grains of sand. Nano DNA (width). Can see with your eyes. Often requires a microscope to see. Requires a highly specialized microscope, such as a Scanning Electron Microscope (SEM), to see. Contact Angle. High contact angle.

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Macro Micro Nano

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  1. Macro Micro Nano

  2. Micro Red blood cells Macro Grains of sand Nano DNA (width) Can see with your eyes Often requires a microscope to see Requires a highly specialized microscope, such as a Scanning Electron Microscope (SEM), to see

  3. Contact Angle High contact angle Low contact angle Hydrophobic surface Hydrophilic surface

  4. Making Predictions OR Rounded Flat 1. Examine the slide under the microscope 2. Predict how a drop of water will behave

  5. SEM of Soot Int. J. Electrochem. Sci., 6 (2011) 1269 – 1276

  6. What is nanotechnology? The nanometer is extremelysmall. At the nanometer scale, many things behave differently. We can use this new behavior to make new technologies.

  7. What is nanotechnology? Nanotechnology is the understanding and control of matter 1 to 100 nanometers in size.

  8. Nanotechnology Anti-biofouling applications Scientists coat surfaces with nanoparticles to prevent biofouling, seen here on a submarine.

  9. Nanotechnology Biomedical applications Research is currently underway that incorporates nano-sized features on implants to prevent bacterial growth, and to encourage the body grow the correct type of cells on the implant.

  10. The Lotus Effect Lotus leaves and nasturtium leaves are self-cleaning due to nano and microscale structures and a waxy coating. Together these features create a superhydrophobic surface. Close-up of a nasturtium leaf, which exhibits the Lotus Effect, with a droplet of water

  11. The Lotus Effect

  12. Hydrophobic Surfaces Water “fearing” Repel water Non-polar Rounded water drop

  13. Superhydrophobic Surfaces • VERY water “fearing” • Non-polar • Nano-scale surface features • Water rolls off when surface is held at an angle • Water drop is very rounded (contact angle greater than 150°)

  14. Hydrophilic Surfaces • Water “loving” • Polar • Flat water drop • Water drop may absorb into material • Leaves a streak of water when rolling off

  15. Water Covers 70% of the Earth’s surface! Essential for life Universal solvent The only molecule that exists naturally as a gas, liquid, and solid Unique properties Chemical Formula: H2O 2 Hydrogens covalently bonded to 1 Oxygen Water Molecule

  16. Properties of Water • Polarity • Hydrogen Bonding • High Surface Tension

  17. Polarity of Water Oxygen attracts electrons much more strongly than hydrogen Partially negative δ- δ+ δ+ Partially positive Water is polar!

  18. Hydrogen Bonding Attraction between water molecules

  19. Surface Tension of Water Polarity and Hydrogen Bonding cause water to form a “skin” of molecules at the surface

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