(Nanotech)_2024[132131231231312123].pptx

NanoTech Slides

1. 1 MM 101 Materials and Nanotechnology Spring 2024

2. 2 https://www.youtube.com/watch?v=OLa8DQkKlyU

3. 3 Technology: Technology is  the application of knowledge for practical purposes. Products are tangible (e.g., machines), and intangible (e.g., software). It involves the application of scientific knowledge, engineering skills, and practical experience to design, build, and operate various devices, machines, software, and systems that make our lives easier, more efficient, and more productive. technology is the key driver of economic growth of countries, regions and cities . Nanotechnology Nanotechnology is the branch of technology that deals with dimensions less than 100 nanometers, especially the manipulation of individual atoms and molecules. It’s the designing, characterization, production and application of structures, devices and systems by controlling shape and size at nanometer scale. Applications are wide and varied, including energy production and storage, drug delivery, materials science, and many others.

4. 4 HOW SMALL IS NANO ?

5. 5 Nanomaterials Nanomaterials may be classified as those materials which have at least one of their dimensions in the nanometric range. Below which there is significant variation in the property of interest compared to microcrystalline materials. Nanocrystalline materials have a grain size of the order of 1−100 nm.

6. 6 CLASSIFICATION OF NANOSTRUCTURED MATERIALS

7. Quantum dots (0D) Quantum dots (QDs) are man-made nanoscale crystals that exhibit unique optical and electronic properties, including the ability to transport electrons and emit light of various colors when exposed to UV light Quantum dots are tiny particles or nanocrystals with diameters in the range of 2-10 nanometers ( 10-50 atoms ).

8. Carbon nanotubes (1D)

9. Nanotechnology What make technology at the nanoscale different from technology at the macroscale?

10. Volume to surface area ratio As objects get smaller they have a much greater surface area to volume ratio 2 cm cube has a surface area of 24 cm 2 and a volume of 8 cm 3 (ratio = 3:1) 10 cm cube has a surface area of 600 cm 2 and a volume of 1000 cm 3 (ratio = 0.6:1) Materials at the nanoscale have a greater surface area to volume ratio than their bulk counterparts. The relative concentration of under-coordinated surface atoms is thus greater for nanomaterials compared to their bulk form

11. 11 From macro- to nanomaterials: the effect on the surface area

12. 12

13. Size Nanoparticle Nanoparticle Volume Surface Area SA:Vol Ratio Diameter (nm) Diameter (um) (nm 3 ) (nm 2 ) (nm 2 /nm 3 ) 1 0.001 0.524 3.14 6 10 0.01 524 314 0.6 100 0.1 523598 31416 0.06 1000 1 5.24E+08 3.14E+06 0.006 10000 10 5.24E+11 3.14E+08 0.0006 100000 100 5.24E+14 3.14E+10 0.00006 1000000 1000 5.24E+17 3.14E+12 0.000006 Some example calculations for volume and surface area of nanoparticles . These calculations use nm as unit of length.

14. 14 How much surface area is increased (exposed) when a cube of 1 cm3 is broken down into cubes (particles) of 1 nm3? When a cube of 1 cm^3 is broken down into cubes of 1 nm^3, the surface area is increased by a factor of 10^18. This is because the surface area of a cube is 6 times the area of one of its faces, and the area of a face is equal to the side length squared. In this case, the side length of the original cube is 1 cm, while the side length of the smaller cubes is 1 nm. So, the surface area of the smaller cubes is (1 nm)^2 = 1 nm^2, while the surface area of the original cube is (1 cm)^2 = 1 cm^2. Therefore, the surface area of the smaller cubes is 10^18 times larger than the surface area of the original cube.

15. Physical properties At very small sizes physical properties (magnetic, electric and optical) of materials can change dramatically. As quantum confinement effects change the electronic structure of the nanomaterial (nanomaterials start to have discrete electronic states, while the bulk material has essentially continuous electronic states). band structure of the nanomaterial changed and consequently modulate its optical and transport properties (i.e., electrical and thermal transport). quantum confinement: small and finite separation between energy levels based on size. Materials with structure at the nanoscale often have unique optical, electronic, thermal (heat), or mechanical properties.

16. NANOMATERIALS - materials of which a section is between 1 and 100 nanometers long. (a billionth of a meter !) Materials with structure at the nanoscale often have unique optical, electronic, thermal (heat), or mechanical properties. Examples of biological materials that are nanomaterials are: The overlapping scales on the wing of the Blue Morpho Butterfly contain nanoscale structures that reflect light to create iridescent colors. Chalk Viruses Wax crystals covering a lotus leaf Spider and spider-mite silk “Spatulae" on the bottom of a Gecko lizard’s feet blood

17. 17 3. Nanoparticles: Coating

18. Coatings - self-cleaning windows and stainproof clothing 3. Nanoparticles: Coating

19. Some clothing manufacturers are making water and stain repellent clothing using nano-sized whiskers in the fabric that cause water to bead up on the surface.

20. ANTIMICROBIAL FABRICS Nanohorizons, a company in Pennsylvania, has started producing a silver nanoparticle material as both a dye and use in polyester and nylon. The silver nanoparticles are toxic to microbes, and so colonies will never form, and clothes using this material will not have odors. 3. Nanoparticles

21. TITANIUM DIOXIDE PARTICLES IN OUR FOODS Candies, sweets and chewing gum have been found to contain the highest levels of titanium dioxide. Powdered doughnuts, candies and gums with hard shells, products with white icing and even bread, mayonnaise, yogurt and other dairy products may also contain titanium dioxide. According to research published in Environmental Science and Technology, up to 36 percent of the titanium dioxide found in nearly 90 food products was in the nanoparticle sizes. TiO2 helps define colors clearly and can prevent UV degradation (cracking and breakdown of materials) . You can find titanium dioxide in food products like candy, coffee creamer, baking and cake decorations, and white sauces 3. Nanoparticles

22. S U NSCREE N S Zinc oxide and T itanium dioxide have been used in sunscreens because of their powerful UV blocking properties but they leave a white coating on the skin, which most people find unpleasant. Many sunscreens and moisturizers available now use these nanoparticles, including products from; Boots Avon The Body Shop L'Oreal Nivea Unilever

23. Catalysts Envirox™ cerium oxide Nanoremediation SAMMS technology to remove mercury Paper photographic paper F ilters nanofibres T ooth p aste to remineralise teeth F ood packaging P aint improved adhesion and anti-fungal qualities/anti-graffiti Clot h es non-staining and anti-radiation B atteries (Black & Decker) phosphate nanocrystal technology Cleaning products 3. Nanoparticles

24. USES FOR CARS

25. DIFFERENT TYPES OF NANOMATERIALS NANOMATERIALS CAN BE DIVIDED INTO 4 TYPES: CARBON-BASED METAL-BASED DENDRIMERS COMPOSITES

26. Potential applications of carbon nanotubes Materials & Chemistry - Ceramic and metallic CNT composites - Polymer CNT composites (heat conducting polymers) - Coatings (e.g. conductive surfaces) - Membranes and catalysis Tips of Scanning Probe Microscopes (SPM) Medicine & Life Science - Medical diagnosis (e.g. Lab on a Chip (LOC)) - Medical applications (e.g. drug delivery) - Chemical sensors - Filters for water and food treatment Electronics & ICT - Lighting elements, CNT based field emission displays - Microelectronic: Single electron transistor - Molecular computing and data storage - Ultra-sensitive electromechanical sensors Micro-Electro-Mechanical Systems (MEMS) Energy - Hydrogen storage, energy storage (super capacitors) - Solar cells - Fuel cells - Superconductive materials

27. CARBON-BASED FULLERENES (ALSO CALLED BUCKYBALLS) Fullerenes are nanomaterials that are made of round hollow cages and have high electrical conductivity and strength. They are named after Buckminster Fuller who designed the Geodesic dome. The illustration shows some of the well-known fullerenes consisting of C60 (A) and C70 atoms (B) of carbon. The number of Carbon atoms can range from 20 to 90.

28. 2) METAL BASED NANOMATERIALS These nanomaterials include quantum dots, nanogold, nanosilver and metal oxides, such as titanium dioxide. A quantum dot is a closely packed semiconductor crystal comprised of hundreds or thousands of atoms, and whose size is on the order of a few nanometers to a few hundred nanometers. Changing the size of quantum dots changes their optical properties.

29. 3) DENDRIMERS These nanomaterials are nanosized polymers built from branched units. The surface of a dendrimer has numerous chain ends, which can be tailored to perform specific chemical functions. This property could also be useful for catalysts, to help with chemical reactions. Also, because three- dimensional dendrimers contain interior cavities into which other molecules could be placed, they may be useful for drug delivery.

30. 4) COMPOSITES Composites combine nanoparticles with other nanoparticles or with larger, bulk-type materials. Clays and Polymers can be used to make them. Nanoparticles are already being added to products ranging from auto parts to packaging materials, to enhance the following properties: Mechanical Thermal Barrier Flame-retardance

31. 34

32. Why is there so much interest/concern about nanotechnology? Enormous potential Huge gaps in knowledge concerning the possible risks Difficulty in detecting and removing Absence of regulation

33. Potential Health Concerns What are the Potentials risks associated with nanotechnology? Adverse health effects in humans from deliberate or accidental exposure Adverse effects on the environment from deliberate or accidental exposure Potentially explosive properties of nanostructures Cause for concern: Nanoparticles are similar in size to many biological structures  easily absorbed by the body. Nanoparticles remain suspended in the environment for extended periods of time. Health Impacts of nanoparticles are expected to be dependant on composition and structure.

34. Risk assessment problems Very difficult to detect without sophisticated equipment Difficult to predict how particles will behave in the environment (dispersed/clumped) Small size may result in particles passing into the body more easily (inhalation, ingestion, absorption) May be more reactive due to surface area to volume ratio Potential to adsorb toxic chemicals Persistence - Longevity of particles in the environment and body are unknown