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اسلاید 1 :
A Nanometer
¢There are 1 billion (1,000,000,000) nanometers in 1 meter
¢There are 1 million (1,000,000) micrometers (or microns) in 1 meter
¢A line of ten hydrogen atoms lined up side by side is 1 nanometer long
¢Your finger nail grows 1 nanometer in 1 second
¢The diameter of your hair is approximately 50,000 nanometers
¢The abbreviation for nanometer is “nm”
اسلاید 2 :
Nanostructures/Nanomaterials
¢Nanostructures are materials that, in at least one dimension, measure approximately 1 – 100 nm
¢Nanostructures or nanomaterials exhibit properties different from their macroscale counterparts (their “big brothers”) such as:
Mechanical strength (how hard they are to break)
Electrical conductivity (how fast electrons flow through them)
Thermal conductivity (how fast heat flows through them)
Chemical reactivity (how well/fast they react with other chemicals)
Transparency (how well you can see through them)
Magnetism (whether or not they are magnetic)
… and many more…
Microstructures, the cousin to nanostructures, typically measure between 100 nanometers and 100 micrometers in at least one dimension, but likely do not exhibit unique properties like nanostructures do
اسلاید 3 :
Types Of Nanostructures/Nanomaterials
¢Nanoparticles or nanospheres: nanoscale lengths are measured in all three dimensions
¢Nanotubes or nanowires or nanorods: nanoscale lengths are measured in two dimensions only
¢Nanoscale thin films or ultra-thin films: nanoscale lengths are measured in one dimension only
¢Nanocomposites: a material comprised of many nanoscale inclusions (such as nanoparticles)
¢Nanostructured materials: a material that exhibits a unique structure that can be measured at the nanoscale
اسلاید 4 :
Common Examples of Nanostructures/Nanomaterials
¢ Quantum dots: nanoparticles 2–10 nm in diameter, made from semiconductors, emit light in a specific wavelength range
¢ Carbon nanotubes: hollow cylinders one to tens of nanometers in diameter, extremely strong (hard to break), conduct heat faster than any other known material
¢ Buckyballs: nanoparticles comprised of exactly 60 carbon atoms (though there are other types), forming a network that resembles a soccer ball
اسلاید 5 :
Why does this happen?
¢Nanostructures obey the same fundamental laws of the universe as everything else in nature
¢But… some things that are negligible (can be ignored) at big scales cannot be ignored at small scales
¢For example:
Imagine you are an electron moving through a “big” copper wire 1 cm in diameter – you may never see the boundaries of the wire because you are so small compared to its diameter
Imagine you are an electron moving through a “small” copper wire 1 nm in diameter (more comparable to the electron’s size) – now you bump into the boundaries of the wire often, which affects how you move through that wire
Therefore, the 1 nm diameter copper wire exhibits different electrical properties than its macroscale counterpart!
اسلاید 6 :
So What is Nanotechnology?
¢Nanotechnology is:
Comprised of nanomaterials with at least one dimension that measures between approximately 1 and 100 nm
Comprised of nanomaterials that exhibit unique properties as a result of their nanoscale size
Based on new nanoscale discoveries across the various disciplines of science and engineering
The manipulation of these nanomaterials to develop new technologies/applications or to improve on existing ones
Used in a wide range of applications from electronics to medicine to energy and more
اسلاید 7 :
Solar Cells
¢Improved efficiencies: novel nanomaterials can harness more of the sun’s energy
¢Lower costs: some novel nanomaterials can be made cheaper than alternatives
¢Flexibility: thin film flexible polymers can be manipulated to generate electricity from the sun’s energy
اسلاید 8 :
Computing
Nanotechnology enhancements provide:
¢Faster processing speeds: miniaturization allows more transistors to be packed on a computer chip
¢More memory: nanosized features on memory chips allow more information to be stored
¢Thermal management solutions for electronics: novel carbon-based nanomaterials carry away heat generated by sensitive electronics
اسلاید 9 :
Clothing
¢Anti-odor properties: silver nanoparticles embedded in textiles kill odor causing bacteria
¢Stain-resistance: nanofiber coatings on textiles stop liquids from penetrating
¢Moisture control: novel nanomaterials on fabrics absorb perspiration and wick it away
¢UV protection: titanium nanoparticles embedded in textiles inhibit UV rays from penetrating through fabric
اسلاید 10 :
¢Higher energy storage capacity and quicker recharge: nanoparticles or nanotubes on electrodes provide high surface area and allow more current to flow
¢Longer life: nanoparticles on electrodes prevent electrolytes from degrading so batteries can be recharged over and over
¢A safer alternative: novel nano-enhanced electrodes can be less flammable, costly and toxic than conventional electrodes
