MATERIALS IN PRACTICE

Transcription

1 MATERIALS IN PRACTICE Office Hours: Tuesday, 16:30-17:30 Phone: Metallurgical and Materials Engineering Department

2 Nanotechnology Nanoscience and nanotechnology primarily deal with the synthesis, characterization, exploration, and exploitation of nanostructured materials. These materials are characterized by at least dimension in the nanometer (1 nm = 10-9 m) range. Nanostructures constitute a bridge between molecules and infinite bulk systems. Individual nanostructures include clusters, quantum dots, nanocrystals, nanowires, and nanotubes, while collections of nanostructures involve arrays, assemblies, and superlattices of the individual nanostructures.

3 Nanotechnology Nano From the Greek word for dwarf and means 10-9, or one-billionth. Here it refers to one-billionth of a meter, or 1 nanometer (nm). 1 nanometer is about 3 atoms long. Nanotechnology Building and using materials, devices and machines at the nanometer (atomic/molecular) scale, making use of unique properties that occur for structures at those small dimensions.

4 Nanotechnology Nanotechnology - Promises What is Nanotechnology Nano-Engineering Nano-Biotechnology Nano-Electronics Nano-Materials Benefits already observed from the design of nanotechnology based products for renewable energy are: An increased efficiency of lighting and heating Increased electrical storage capacity A decrease in the amount of pollution from the use of energy

5 Nanotechnology Nanochemistry: In its broadest terms, the utilization of synthetic chemistry to make nanoscale building blocks of different size and shape, composition and surface structure, charge and functionality. In a self-assembly construction process, spontaneous, directed by templates or guided by chemically or lithographically defined surface patterns, they may form architectures that perform an intelligent function and portend a particular use. Nanoscience and nanotechnology congers up visions of making, imaging, manipulating and utilizing things really small Stimulus for this growth can be traced to new and improved ways of making and assembling, positioning and connecting, imaging and measuring the properties of nanomaterials with controlled size and shape, composition and surface structure, charge and functionality for use in the macroscopic real world.

6 Nanotechnology How small is a nanometer? (and other small sizes)

7 Nanotechnology The Scale of Things Nanometers and More

8 Nanotechnology The Scale of Things Nanometers and More SCI316/course%20files/9.+Probing+th e+nanoscale.pdf

9 Nanotechnology Nanostructures and Their Assemblies Nanostructure Size Material Clusters, nanocrystals Quantum dots Radius, 1 10 nm Insulators, semiconductors, metals, magnetic materials Other nanoparticles Radius, nm Ceramic oxides Nanobiomaterials, Photosynthetic reaction center Nanowires Nanotubes Radius, 5 10 nm Diameter, nm Diameter, nm Membrane protein Metals, semiconductors, oxides, sulfides, nitrides Carbon, layered Chalcogenides, BN, GaN Nanobiorods Diameter, 5 nm DNA Two-dimensional arrays of nanoparticles Surfaces and thin films Three-dimensional superlattices of nanoparticles Area, several nm 2 µm 2 Thickness, nm Several nm in three dimensions Metals, semiconductors, magnetic materials Insulators, semiconductors, metals, DNA Metals, semiconductors, magnetic materials

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12 Nanotechnology Why is Small Good? Faster Lighter Can get into small spaces Cheaper More energy efficient Different properties for very small structures

13 Nanotechnology Reasons to Miniaturize Miniaturization Attributes Low energy and little material consumed Arrays of sensors Small Favorable scaling laws Batch and beyond batch techniques Disposable Breakdown of macro laws in physics and chemistry Smaller building blocks Limited resources Reasons Redundancy, wider dynamic range, increased selectivity through pattern recognition Small is lower in cost, minimally invasive Forces that scale with a low power become more prominent in the micro domain; if these are positive attributes then miniaturization favorable (e.g. surface tension becomes more important than gravity in a narrower capillary) Lowers cost Helps to avoid contamination New physics and chemistry might be developed The smaller the building blocks, the more sophisticated the system that can be built

14 Nanotechnology

15 Why you want nanotechnology in your life? Nanotechnology will increase your standard of living no ifs, ands, or buts. Done right, it will make our lives more secure, improve healthcare delivery, and optimize our use of limited resources. Pretty basic stuff, in other words. Mankind has spent millennia trying to fill these needs, because it has always known that these are the things it needs to ensure a future for itself. If nanotechnological applications pan out the way we think they will pan out, we are one step closer to ensuring that future

16 Security Security is a broad field, covering everything from the security of our borders to the security of our infrastructure to the security of our computer networks. Here s our take on how nanotechnology will revolutionize the whole security field: Superior, lightweight materials: Imagine materials ten times stronger than steel at a fraction of the weight. With such materials, nanotechnology could revolutionize tanks, airframes, spacecraft, skyscrapers, bridges, and body armor, providing unprecedented protection. Composite nanomaterials may one day lead to shape-shifting wings instead of the mechanical flaps on current designs. Kevlar, the backbone fiber of bulletproof vests, will be replaced with materials that not only provide better protection but store energy and monitor the health status of our soldiers. A taste of what s to come: MIT was awarded a $50 million Army contract in 2002 to launch the Institute for Soldier Nanotechnologies (ISN) developing artificial muscles, biowarfare sensors, and communications systems. Powerful munitions: Nanometals, nano-sized particles of metal such as nanoaluminum, are more chemically reactive because of their small size and greater surface area. Varying the size of these nanometals in munitions allows us to control the explosion, minimizing collateral damage. Incorporating nanometals into bombs and propellants increases the speed of released energy with fewer raw materials consumed more (and better-directed) bang for your buck.

17 Security Advanced computing: More powerful and smaller computers will encrypt our data and provide round-the-clock security. Quantum cryptography cryptography that utilizes the unique properties of quantum mechanics will provide unbreakable security for businesses, government, and military. These same quantum mechanics will be used to construct quantum computers capable of breaking current encryption techniques (a needed advantage in the war against terror). Additionally, quantum computers provide better simulations to predict natural disasters and pattern recognition to make biometrics identification based on personal features such as face recognition possible. Increased situational awareness: Chemical sensors based on nanotechnology will be incredibly sensitive - capable, in fact, of pinpointing a single molecule out of billions. These sensors will be cheap and disposable, forewarning us of airport-security breaches or anthrax-laced letters. These sensors will eventually take to the air on military unmanned aerial vehicles (UAVs), not only sensing chemicals but also providing incredible photo resolutions. These photos, condensed and on an energy-efficient, high resolution, wristwatch-sized display, will find their way to the soldier, providing incredible real-time situational awareness at the place needed most: the front lines.

18 Healthcare Making the world around us more secure is one thing, but how about making the world inside us more secure? With nanotechnology, what s beneath our skin is going to be more accessible to us than it s ever been before. Here s what we see happening: Diagnostics: Hospitals will benefit greatly from nanotechnology with faster, cheaper diagnostic equipment. The lab-on-a-chip is waiting in the wings to analyze a patient s ailments in an instant, providing point-of care testing and drug application, thus taking out a lot of the diagnostic guesswork that has plagued healthcare up to now. New contrast agents will float through the bloodstream, lighting up problems such as tumors with incredible accuracy. Not only will nanotechnology make diagnostic tests better, but it will also make them more portable, providing time sensitive diagnostics out in the field on ambulances. Newborn children will have their DNA quickly mapped, pointing out future potential problems, allowing us to curtail disease before it takes hold. Novel drugs: Nanotechnology will aid in the delivery of just the right amount of medicine to the exact spots of the body that need it most. Nanoshells, approximately 100 nm in diameter, will float through the body, attaching only to cancer cells. When excited by a laser beam, the nanoshells will give off heat in effect, cooking the tumor and destroying it. Nanotechnology will create biocompatible joint replacements and artery stents that will last the life of the patient instead of having to be replaced every few years.

19 Resources The only thing not in short supply these days is more human beings and we re not about to see a shortage of them any time soon. If we are going to survive at all - much less thrive - we are going to need to find ways to use the riches of this world more efficiently. Here s how nanotechnology could help: Energy: Nanotechnology is set to provide new methods to effectively utilize our current energy resources while also presenting new alternatives. Cars will have lighter and stronger engine blocks and frames and will use new additives making fuel more efficient. House lighting will use quantum dots - nanocrystals 5 nm across - in order to transform electricity into light instead of wasting away into heat. Solar cells will finally become cost effective and hydrogen fuel cells will get a boost from nanomaterials and nanocomposites. Our Holy Grail will be a reusable catalyst that quickly breaks down water in the presence of sunlight, making that long-wishedfor hydrogen economy realistic. That catalyst, whatever it is, will be constructed with nanotechnology. Water: Nanotechnology will provide efficient water purification techniques, allowing third-world countries access to clean water. When we satisfy our energy requirements, desalinization of water from our oceans will not only provide enough water to drink but also enough to water our crops.

20 Nanotechnology Commercialization Timeline

21 Nanotechnology Some of the important concerns of materials scientists in the nanoscience area are: Nanoparticles or nanocrystals of metals and semiconductors, nanotubes, nanowires, and nanobiological systems. Assemblies of nanostructures (e.g., nanocrystals and nanowires) and the use of biological systems, such as DNA as molecular nanowires and templates for metallic or semiconducting nanostructures. Theoretical and computational investigations that provide the conceptual framework for structure, dynamics, response, and transport in nanostructures. Applications of nanomaterials in biology, medicine, electronics, chemical processes, high-strength materials, etc.

22 Nanotechnology The physical and chemical properties of nanomaterials can differ significantly from those of the atomic-molecular or the bulk materials of the same composition. The uniqueness the structural characteristics, energetics, response, dynamics, and chemistry of nanostructures constitutes the basis of nanoscience. Suitable control of the properties and response of nanostructures can lead to new devices and technologies. The themes underlying nanoscience and nanotechnology are twofold: one is the bottom-up approach, that is, the miniaturization of the components, articulated by Feynman, who stated in the 1959 lecture that there is plenty of room at the bottom ; and the other is the approach of the self-assembly of molecular components, where each nanostructured component becomes part of a suprastructure. The latter approach is akin to that of Jean-Marie Lehn.

23 Nanotechnology Bottom-up approaches These seek to arrange smaller components into more complex assemblies. DNA nanotechnology utilizes the specificity of Watson Crick basepairing to construct well-defined structures out of DNA and othernucleic acids. Approaches from the field of "classical" chemical synthesis (inorganic and organic synthesis) also aim at designing molecules with welldefined shape. More generally, molecular self-assembly seeks to use concepts of supramolecular chemistry, and molecular recognition in particular, to cause single-molecule components to automatically arrange themselves into some useful conformation. Atomic force microscope tips can be used as a nanoscale "write head" to deposit a chemical upon a surface in a desired pattern in a process called dip pen nanolithography. This technique fits into the larger subfield of nanolithography.

24 Nanotechnology Bottom-up approaches

25 Nanotechnology Top-down approaches These seek to create smaller devices by using larger ones to direct their assembly. Many technologies that descended from conventional solid-state silicon methods for fabricating microprocessors are now capable of creating features smaller than 100 nm, falling under the definition of nanotechnology. Giant magnetoresistance-based hard drives already on the market fit this description, as do atomic layer deposition (ALD) techniques. Peter Grünberg and Albert Fert received the Nobel Prize in Physics in 2007 for their discovery of Giant magnetoresistance and contributions to the field of spintronics. Solid-state techniques can also be used to create devices known as nanoelectromechanical systems or NEMS, which are related tomicroelectromechanical systems or MEMS. Focused ion beams can directly remove material, or even deposit material when suitable precursor gasses are applied at the same time. For example, this technique is used routinely to create sub-100 nm sections of material for analysis in Transmission electron microscopy. Atomic force microscope tips can be used as a nanoscale "write head" to deposit a resist, which is then followed by an etching process to remove material in a top-down method.

26 Nanotechnology The melting point of gold particles decreases dramatically as the particle size gets below 5 nm

27 Nanotechnology Size-Dependent Properties : Metallic Particles

28 Nanotechnology The color of gold changes as the particle size changes at the nanometer scale.

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36 1985: R. Smalley, R. Curl and H. Kroto discovers Buckminsterfullerene or Bucky ball. Nobel in A C 60 molecule Nano-abacus of C 60 molecules

37 General belief and excitement over buckyballs lies in their sheer strength for use in building materials. There is considerable belief that in the 21st century buckyballs and buckytubes may replace silicon as the building blocks for future electronic devices in computers and communication devices. Buckytubes are also the strongest materials known and are already finding applications in composite materials, as surface coatings to improve wear resistance, and as components in scientific instruments. Buckyballs may find application in drug delivery systems. Because fullerenes are very large graphitic systems, they can easily accommodate extra electrons. When you add three electrons to C60 you get ionic solids of the general formula A3C60, where A is any metal in Group I (lithium, sodium, potassium, rubidium, cesium). These materials are actually metals, and display sup erconductivity at somewhat low temperatures. Current research is aimed at getting the maximum superconducting temperature (or Tc) to higher values. C60 is just the right size to fit into the activ e cavity of HIV Protease, an enzyme important to the activity of the virus which causes AIDS. Cramming a buckyball into the active cavity would deactivate the enzyme and kill the virus. Ways of getting the molecule to the enzyme are under investigation.

38 Carbon Nanotubes 1991: Sumio Ijima discovers carbon nanotubes 1997: DNA based micromechanical device built

39 Carbon Nanotubes Carbon nanotubes (CNTs; also known as buckytubes) are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-todiameter ratio of up to 132,000,000:1, significantly larger than any other material. These cylindrical carbon molecules have novel properties, making them potentially useful in many applications in nanotechnology, electronics, optics, and other fields of materials science, as well as potential uses in architectural fields. Armchair and zigzagcarbon nanotube Multiwall nanotubes

40 Nanotechnology for Aerospace Application

41 Carbon Nanotubes Offer a Remarkable Combination of Properties of High Potential

42 Carbon Nanotubes Offer a Remarkable Combination of Properties of High Potential Bucky Paper

43 Graphene: the nano-sized material with a massive future Graphene is a one-atom thick layer of carbon atoms arranged in a honeycomb lattice. Graphene's amazing properties excite and confound in equal measure. How can something one million times thinner than a human hair be 300 times stronger than steel and 1,000 times more conductive than silicon? The very first application where graphene is going to be used is probably as a replacement for (the relatively expensive metal) indium selenide in solar cells.

44 Nanotechnology for Aerospace Application Estimated Impact of Carbon Nanotube Innovations

45 Nanotechnology Nano, Food & Agriculture Fertilizer (more efficient delivery) Water conservation (nanoporous membrane from organic waste reduces consumption by 50%) Environmentally friendly packaging with improved performance (shelf life, antimicrobial, interactive/smart) Sensors (predict, control and improve yield) Functionalized foods (targeted to deliver nutrients in body where one needs them; improved taste and texture) Growing metal nanoparticles (e.g. Ag in fungi): green manufacturing, no solvents involved

46 Nanotechnology Nano and Energy Lighter materials (transport sector) Higher temperature coatings (efficiency) Storage (electrode material for batteries, Hydrogen storage, ) Generation (fuel cells) Insulation (smart windows) Manufacturing (catalysis)

47 SOLAR CELLS Nanotechnology enhancements provide: 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

48 PHOTOVOLTAIC SOLAR CELLS

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51 BATTERIES Nanotechnology enhancements provide: 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 nanoenhanced electrodes can be less flammable, costly and toxic than conventional electrodes

52 WATER PURIFICATION Nanotechnology enhancements provide: Easier contamination removal: filters made of nanofibers that can remove small contaminants Improved desalination methods: nanoparticle or nanotube membranes that allow only pure water to pass through Lower costs Lower energy use

53 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

54 NEXT GENERATION COMPUTING Nanotechnology enhancements provide: The ability to control atomic scale phenomena: quantum or molecular phenomena that can be used to represent data Faster processing speeds Lighter weight and miniaturized computers Increased memory Lower energy consumption

55 NANOROBOTICS Nanotechnology enhancements provide: The ability to control atomic scale phenomena: quantum or molecular phenomena that can be used to represent data Faster speeds processing Lighter weight and miniaturized computers Increased memory Lower consumption energy Nanorobotics is an emerging and wide-spanning field. It can either be defined as a system where the dimensions of the parts approach the scale of a nanometer, or where the positional resolution approaches the scale of a nanometer. A typical concept of a nanorobot is a controllable device at the size of bacteria, which can be used in the human body for medical purposes. This does not exist yet, but research might eventually lead us there.

56 DRUG DELIVERY Nanotechnology enhancements provide: New vehicles for delivery: nanoparticles such as buckyballs or other cage-like structures that carry drugs through the body Targeted delivery: nano vehicles that deliver drugs to specific locations in body Time release: nanostructured material that store medicine in nanosized pockets that release small amounts of drugs over time

57 SPORTING GOODS AND EQUIPMENT Nanotechnology enhancements provide: Increased strength of materials: novel carbon nanofiber or nanotubebased nanocomposites give the player a stronger swing Lighter weight materials: nanocomposites are typically lighter weight than their macroscale counterparts

58 SPORTING GOODS AND EQUIPMENT Added advantages of incorporated nanomaterials in sporting equipments.

59 CLOTHING Nanotechnology enhancements provide: 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

60 AUTOMOTIVE INDUSTRY Nanotechnology enhancements provide: The automotive sector is a major consumer of material technologies and nanotechnologies promise to improve the performance of existing technologies significantly. Applications range from already existing paint quality, fuel cells, batteries, wearresistant tires, lighter but stronger materials, ultra-thin anti-glare layers for windows and mirrors to the futuristic energy-harvesting bodywork, fully selfrepairing paint, switchable colors, shapeshifting skin. Increased strength of materials: novel carbon nanofiber or nanotube nanocomposites are used in car bumpers, cargo liners and as stepassists for vans Lighter weight materials: lightweight nanocomposites mean less fuel is used to make the car go

61 AUTOMOTIVE INDUSTRY Nanotechnology enhancements provide: The basic trends that nanotechnology enables for the automobile are lighter but stronger materials (for better fuel consumption and increased safety) improved engine efficiency and fuel consumption for gasoline-powered cars (catalysts; fuel additives; lubricants) reduced environmental impact from hydrogen and fuel cellpowered carsimproved and miniaturized electronic systems better economies (longer service life; lower component failure rate; smart materials for self-repair)

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64 AUTOMOTIVE INDUSTRY Outlook: Today, only a limited number of nanotech products are integrated into automotive applications. The performance-to-cost ratio is a major hurdle for broader market acceptance, since nano-objects are still expensive and their added value is not always sufficient to balance their cost. The evolution of these fillers is linked to nanoobject prices, which will certainly decrease as production capabilities develop. Generally speaking, nanofiller prices are much higher than those of standard fillers. This increase in rawmaterial costs can be balanced by a reduction of the filler content and the reduced final weight of parts, combined with improved properties. Thus, the addition of nanofillers often requires rethinking the part (design changes) and the processing technologies (new moulds, modified rheological behaviour, etc.), which also needs to be considered in the part s cost calculations. Nanocomposites are developing in the automotive market, but proof of the competitive advantage of nano-objects remains to be confirmed, taking into account cost and performance. Significant further development and modification of current processing may yet be required (rethinking of the global system, including part design). Moreover, nanotoxicity and recycling are important subjects that must be taken into account while using these new materials.

65 FOOD AND BEVERAGE Nanotechnology enhancements provide: Better, more environmentally friendly adhesives for fast food containers Anti-bacterial properties: Nano silver coatings on kitchen tools and counter-tops kill bacteria/microbes Improved barrier properties for carbonated beverages or packaged foods: nanocomposites slow down the flow of gas or water vapor across the container, increasing shelf life Food packaging For now, nanotechnology is likely to have a bigger impact in food packaging. Nanoscale polymers are already used in some packaging to prevent oxygen leaking through, which extends a product's shelf life. Researchers have developed sensors based on nanoparticles that change colour in response to changing acidity levels or the presence of bacteria, which could indicate when food has spoiled. Eventually, such sensors could even trigger the release of preservatives when they detect food beginning to spoil.

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67 BODY ARMOR Nanotechnology enhancements provide: Stronger materials for better protection: nanocomposites that provide unparalleled strength and impact resistance Flexible materials for more formfitting wearability: nanoparticle-based materials that act like liquid armor Lighter weight materials: nanomaterials typically weigh less than their macroscale counterparts Dynamic control: nanofibers that can be flexed as necessary to provide CPR to soldiers or stiffen to furnish additional protection in the face of danger Kevlar body armor

68 Nanotechnology for Aerospace Application

69 Nanotechnology will be in Future of Flight In futuristic scenario, aircraft could weight as little as half of the conventional aircraft manufactured with today's materials. Such novel materials would be extremely flexible, allowing the wing to reshape instantly and remaining extremely resistant to damage at the same time. In addition, these materials would have self healing functionality. The high strength to weight ratio of nano materials could enable new airplane design that can withstand crashes and protect the passages against injury NASA, 2001

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71 Nanotechnology for Aerospace Application

72 Nanotechnology for Aerospace Application Nano Roadmap 12 Priorities

73 Nanotechnology for Aerospace Application

74 SENSORS Nanotechnology enhancements provide: Higher sensitivity: high surface area of nanostructures that allows for easier detection of chemicals, biological toxins, radiation, disease, etc. Miniaturization: nanoscale fabrication methods that can be used to make smaller sensors that can be hidden and integrated into various objects

75 CANCER Nanotechnology enhancements provide: This is a picture of two cancer cells splitting and dividing to become four cancer cells. Earlier detection: specialized nanoparticles that target cancer cells only these nanoparticles can be easily imaged to find small tumors Improved treatments: infrared light that shines on the body is absorbed by the specialized nanoparticles in the cancer cells only, leading to an increased localized temperature that selectively kills the cancer cells but leaves normal cells unharmed

76 In order to successfully detect cancer at its earliest stages, scientists must be able to detect molecular changes even when they occur only in a small percentage of cells. This means the necessary tools must be extremely sensitive. The potential for nanostructures to enter and analyze single cells suggests they could meet this need.

77 Miniaturization will allow the tools for many different tests to be situated together on the same small device. Researchers hope that nanotechnology will allow them to run many diagnostic tests simultaneously.

78 Another interesting nanodevice is the nanopore. Improved methods of reading the genetic code will help researchers detect errors in genes that may contribute to cancer. Scientists believe nanopores, tiny holes that allow DNA to pass through one strand at a time, will make DNA sequencing more efþcient. As DNA passes through a nanopore, scientists can monitor the shape and electrical properties of each base, or letter, on the strand. Because these properties are unique for each of the four bases that make up the genetic code, scientists can use the passage of DNA through a nanopore to decipher the encoded information, including errors in the code known to be associated with cancer.

79 Nanotechnology may also be useful for developing ways to eradicate cancer cells without harming healthy, neighboring cells. Scientists hope to use nanotechnology to create therapeutic agents that target speciþc cells and deliver their toxin in a controlled, time-released manner.

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84 Nanotechnology The Risk of Nanotechnology The REAL Risk: Utilizing nanotechnology without evaluating the consequences: assess advantages and down sides Example: The widespread introduction of nanoparticulates into the ecosphere when their toxicological impact is not known

85 THE END Thanks for your kind attention

86 Any Questions