NANO-TECHNOLOGY OF APPLICATIONS OF NANOTECH-NOLOGY
NANO-TECHNOLOGY OF APPLICATIONS OF NANOTECH-NOLOGY
INTRODUCTION:
Nanotechnology shortened to “Nanotech” is the study of the control of matter on an atomic and molecular scale. Atoms are the building blocks for all matter in our universe. You and everything around you are made of atoms. Nature has perfected the science of manufacturing matter molecularly. For instance, our bodies are assembled in a specific manner from millions of living cells. Cells are nature’s nanomachines. At the atomic scale, elements are at their most basic level. On the nanosc+-ale, we can potentially put these atoms together to make almost anything.
Nanotechnology is a fundamental, enabling technology, allowing us to do new things in almost every conceivable technological discipline. Nano means small (10A-9 m) but of high potency, and emerging with large applications piercing through all the discipline of knowledge, leading to industrial and technological growth.
Richard Feynman has been credited with introducing the concept of nanotechnology (creation of devices at the molecular scale) in his book There’s Plenty of Room at the Bottom in 1959.
Nanotechnology deals with materials and machines on an incredibly tiny scale — less than one billionth of a meter. In its original sense, ‘nanotechnology’ refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, high-performance products. The potential of this technology to change our world is indeed truly staggering. It will affect every aspect of our lives, from medicine, to the power of our computers, the energy we require, the cars we drive, the building we live in, and even the clothes we wear. It will continuously generate new capabilities, new products, new markets. Its impact in society will be broad.
HOW NANOTECHNOLOGY WORKS
The transition from microparticles to nanoparticles can lead to a number of changes in physical properties. Two of the major factors in this are the increase in the ratio of surface area to volume, and the size of the particle moving into the realm where quantum effects predominate. The increase in the surface-area-to-volume ratio, which is a gradual progression as the particle gets smaller, leads to increasing dominance of the behavior of atoms on the surface of a particle over that of those in the interior of the particle.
This affects both the properties of the particle in isolation and its interaction with other materials. High surface area is a critical factor in the performance of catalysis and structures such as electrodes, allowing improvement in performance of such technologies as fuel cells and batteries. It is conceived that this emerging developmental research will allow us to arrange atoms and molecules in most of the ways permitted by physical laws.
Their optical properties, e.g. fluorescence, become a function of the particle diameter. When brought into a bulk material, nanoparticles can strongly influence the mechanical properties of the material, like stiffness or elasticity. For example, traditional polymers can be reinforced by nanoparticles resulting in novel materials which can be used as lightweight replacements for metals. Therefore, an increasing societal benefit of such nanoparticles can be expected. Such nanotechnologically enhanced materials will enable a weight reduction accompanied by an increase in stability and an improved functionality.
Nanotechnology is rapidly becoming an interdisciplinary field. Biologists, chemists, physicists, and engineers are all involved in the study of substances at the nanoscale.
Nanotechnology Helps us to:
- Get essentially every atom in the right place.
- Make almost any structure consistent with the laws of physics that we can specify in molecular detail.
- Have manufacturing costs not greatly exceed the cost of the required raw materials and energy.
Four Phases of Development Visualised
The present phase is that of passive nanostructures, materials designed to perform one task. The second phase, which we are just entering, introduces active nanostructures for multitasking; for example, actuators, drug delivery devices, and sensors. The third generation is expected to begin emerging around 2010 and will feature nanosystems with thousands of interacting components. A few years after that, the first integrated nanosystems, functioning much like a mammalian cell with hierarchical systems within systems, are expected to be developed.
CONCEPTS COMMONLY ASSOCIATED WITH NANOTECHNOLOGY
There are two concepts commonly associated with nanotechnology
Positional Assembly: Clearly, we would be happy with any method that simultaneously achieved the first three objectives. However, this seems difficult without using some form of positional assembly (to get the right molecular parts in the right places) and some form of massive parallelism (to keep the costs down).
The need for positional assembly implies an interest in molecular robotics, e.g., robotic devices that ire molecular both in their size and precision. These molecular scale positional devices are likely to resemble very small versions of their everyday macroscopic counterparts. Positional assembly is frequently used in normal macroscopic manufacturing today, and provides tremendous advantages. Imagine trying to build a bicycle with both hands tied behind your back! The idea of manipulating and positioning individual atoms and molecules is still new and takes some getting used to. However, as Feynman aid in a classic talk in 1959: “The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom.” We need to apply at the molecular scale the concept lat has demonstrated its effectiveness at the macroscopic scale: making parts go where we want by putting them where we want.
Massive Parallelism: One robotic arm assembling molecular parts is going to take a long time to assenl the anything large – so we need lots of robotic arms: this is what we mean by massive parallelism. While earlier proposals achieved massive parallelism through self-replication, today’s “best guess” is that future molecular manufacturing systems will use some form of convergent assembly. In this process vast numbers of small parts are assembled by vast numbers of small robotic arms into larger parts, those larger parts are assembled by large robotic arms into still larger parts, and so forth. If the size of the parts doubles at each iteration, we can go from one-nanometer parts (a few atoms in size) to one-meter parts (almost as big as a person) in only 30 steps.
Ø Apocalyptic Goo
Eric Drexler, the man who introduced the word nanotechnology, presented a frightening apocalyptic vision–self-replicating nanorobots malfunctioning, duplicating themselves a trillion times over, rapidly consuming the entire world as they pull carbon from the environment to build more of themselves. It’s called the “grey goo’ scenario, where a synthetic nano-size device replaces all organic material. Another scenario involves nanodevices made of organic material wiping out the Earth – the “green goo” scenario.
COMMERCIALISED NANOMATERIALS
Ø Carbon Nanotube
The discovery that carbon could form stable, ordered structures other than graphite and diamond stimulated researchers worldwide to search for other new forms of carbon. The search was given new impetus when it was shown in 1990 that C60 could be produced in a simple arc-evaporation apparatus readily available in all laboratories. It was using such an evaporator that the Japanese scientist Sumio lijima discovered fullerene-related carbon nanotubes in 1991. Carbon nanotubes are molecular-scale tubes of graphitic carbon with outstanding properties. They are among the stiffest and strongest fibres known, and have remarkable electronic properties and many other unique characteristics. Commercial applications have been rather slow to develop, however, primarily because of the high production costs of the best quality nanotubes.
These cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science, as well as potential uses in architectural fields. They exhibit extraordinary strength and unique electrical properties and are efficient conductors of heat.
Ø Nanotube Applications
The properties of carbon nanotubes have caused researchers and companies to consider using them in several fields. For example, because carbon nanotubes have the highest strength-to-weight ratio of any known material IT researchers at NASA are combining nanotubes with other materials into composites that can be used to build lightweight spacecraft.
Another property of nanotubes is that they can easily penetrate membranes such as cell walls. In (act, nanotubes’ long, narrow shape make them look like miniature needles, so it makes sense that they can function like a needle at the cellular level. Medical researchers are using this property by attaching molecules that are c attracted to cancer cells to nanotubes to deliver drugs directly to the diseased cells.
Another interesting property of nanotubes is that their electrical resistance changes significantly when other molecules attach themselves to the carbon atoms. Companies are using this property to develop sensors that can detect chemical vapors such as carbon monoxide or biological molecules.
These are just a few of the potential uses of carbon nanotubes. The following survey of carbon nanotube applications introduces these and many other uses.
A survey of carbon nanotube applications under development:
- Researchers and companies are working to use carbon nanotubes in various fields. The list below introduces many of these uses.
- Strong, lightweight composites of carbon nanotubes and other materials that can be used to build lightweight spacecraft.
- Cables made from carbon nanotubes strong enough to be used for the Space Elevator to drastically reduce the cost of lifting people and materials into orbit.
- Taking advantage of nanotubes’ ability to enter cancer cells by attaching targeting molecules that have an affinity to cancer cells as well as anti-cancer drugs to the nanotubes which safely transports an anti-cancer drug are tough the bloodstream to the tumor.
- Stronger bicycle components made by adding carbon nanotubes to a matrix of carbon fibers. Improve the healing process for broken bones by providing a carbon nanotube scaffold for new bone material to grow on.
- Sensors using carbon nanotube detection elements capable of detecting a range of chemical vapors. These depend upon the fact that the resistance of a carbon nanotube changes in the presence of a chemical
- Static dissipative plastic molding compounds containing nanotubes that can be used to make parts such as automobile fenders that can be electrostatically painted.
- Carbon nanotubes used to direct electrons to illuminate pixels, resulting in a lightweight, millimeter-thick “nano emissive” display panel.
Using carbon nanotubes to improve the efficiency of organic solar cells.
Printable electronics devices using nanotube “ink” in inkjet printers.
Transparent, flexible electronics devices using arrays of nanotubes.
Ø Dendrimers
Dendrimers are a new class of polymeric materials. They are highly branched monodisperse macromolecules. The structure of these materials has a great impact on their physical and chemical properties. As a result of their unique behavior dendrimers are suitable for a wide range of biomedical and industrial applications. First discovered led in the early 1980s by Donald Tomalia and co-workers [1], these hyperbranched molecules were called dendrimers. The term originates from ‘dendron’ meaning a tree in Greek. Dendritic molecules are repeatedly branched species that are characterized by their structure perfection. The area of dendritic molecules can roughly be divided into the low-molecular-weight and the high-molecular-weight species. The first category includes dendrimers and dendrons whereas the second encompasses dendronized polymers, hyperbranched polymers, and brush polymers. There are attempts to use dendrimers in the targeted delivery of drugs and other therapeutic agents. Drug molecules can be loaded both in the interior of the dendrimers as well as attached to the surface groups.
Ø Quantum Dot
They were discovered by Louis E. Brus. Quantum dots, also known as nanocrystals, are a special class of materials known as semiconductors, which are crystals. Quantum dots are a unique class of semiconductors because they e so small, ranging from 2-10 nanometers (10-50 atoms) in diameter. At these small sizes materials behave differently, giving quantum dots unprecedented tunability and enabling never before seen applications to science and technology. Semiconductors are a cornerstone of the modern electronics industry and make possible applications such as the Light Emitting Diode and personal computers. Being zero-dimensional, quantum dots have a harper density of states than higher-dimensional structures. As a result, they have superior transport and optical properties and are being researched for use in diode lasers, amplifiers, and biological sensors. Quantum dots lay be excited within the locally enhanced electromagnetic field produced by the gold nanoparticles. The new generations of quantum dots have far-reaching potential for the study of intracellular processes at the single-molecule level, high-resolution cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
APPLICATIONS OF NANOTECH-NOLOGY
Ø Medicine
The health care industry is predicted to receive the first significant benefits of nanotechnology. The driving force behind this prediction is that biological structures are within the size scale that researchers are now able to manipulate and control.
Investigators are looking to nanotechnology to develop highly sensitive disease detectors, drug delivery systems that only target the disease and not the surrounding healthy tissue, and nanoscale building blocks to help repair skin, cartilage, and/or bone.
The biological and medical research communities have exploited the unique properties of nanomaterials IT various applications (e.g., contrast agents for cell imaging and therapeutics for treating cancer). Functionalities can be added to nanomaterials by interfacing them with biological molecules or structures. The size of nanomaterials is similar to that of most biological molecules and structures; therefore, nanomaterials can be useful for both in vivo and in vitro biomedical research and applications. Thus far, the integration of nanomaterials with biology has LED to the development of diagnostic devices, contrast agents, analytical tools, physical therapy applications, and drug delivery vehicles.
Ø Diagnostics
Some diseases do not exhibit recognizable symptoms until they are well advanced. Often the earlier the disease is detected the better the benefits of treatment.
One of the goals of researchers working at the nanoscale is to develop tools that will enable doctors to detect life-threatening diseases before they overwhelm the body. For example, doctors would like to be able to diagnose breast cancer when the tumor mass is 100-1000 cells. Right now with techniques like mammography, a tumor mass needs to be more than a million cells before an accurate clinical diagnosis can be made.
Sensors based upon nanoscale materials have the potential to be millions of times more sensitive than their macro-scale counterparts. They could also be designed to detect hundreds or even thousands of diseases at the same time. Nanotechnology-on-a-chip is one more dimension of lab-on-a-chip technology. Biological tests measuring the presence or activity of selected substances become quicker, more sensitive, and more flexible when certain nanoscale particles are put to work as tags or labels. Magnetic nanoparticles, bound to a suitable antibody, are used to label specific molecules, structures, or microorganisms. Gold nanoparticles tagged with short segments of DNA can be used for the detection of genetic sequences in a sample. Multicolor optical coding for biological assays has been achieved by embedding different-sized quantum dots into polymeric microbeads. Nanopore technology for the analysis of nucleic acids converts strings of nucleotides directly into electronic signatures.
Typhoid Detection Kit: Typhoid Detection Kit has been developed by DRDE, Gwalior using the nanosensor developed by Prof. A.K. Sood, and his team from IISc, Bangalore. Typhoid fever is caused by Salmonella typhi.
Alex agglutination-based test has been developed at DRDE, Gwalior using recombinant DNA technology and immunological technique for rapid diagnosis of typhoid infection. The test detects S. Typhi antigen directly in the patient’s serum within 1-3 minutes which is very important for initiating early treatment and saving human life.
Ø Biological Markers
Researchers are examining the hypothesis that there are biological markers in the body for disease, but that some of these biological markers are at such small concentrations that current methods can not sense them.
Recently researchers identified a biological marker for Alzheimer’s disease and have been able to detect minute concentrations of it using nanotechnology (i.e., the bio-barcode process developed by C. Mirkin and colleagues). If successful, this could be the first tool for early diagnosis of Alzheimer’s disease. Experiments are also underway to use this bio-barcode process for other diseases like AIDS and many forms of cancer.
Ø Power
Gas flow-induced generation of voltage from solids. Prof AK Sood, Professor of physics at MSc, and his student Shankar Ghosh has studied and experimented and found that the liquid flow in carbon nanotubes can generate electric current. One of the most exciting applications to emerge from the discovery is the possibility of a heart pacemaker-like device with nanotubes, which will sit in the human body and generate power from blood Instead of batteries, the device will generate power by itself to regulate defective heart rhythm.
The IISc has transferred the exclusive rights of the technology to an American start-up Trident Metrologies. They will develop the prototypes and commercialize the gas flow sensors.
Ø Regeneration
Unlike other cells in the body, once cells in the central nervous system (spinal cord or brain cells) are mature, they cannot reproduce themselves as other cells can.
If these cells are damaged through accident or disease, patients must learn to live with the impact.
Nanotechnology may provide some promise. Few are using nanotechnology to engineer a gel that spurs the growth of nerve cells. The gel fills the space between existing cells and encourages new cells to grow. While still in the experimental stage, this process could eventually be used to re-grow lost or damaged spinal cord or brain cells.
Researchers are also investigating the use of nanotechnology to keep the body from rejecting artificial parts, and to stimulate the body to regrow bone and other types of tissue.
Ø Tissue Engineering
Nanotechnology can help to reproduce or to repair damaged tissue. This so called “tissue engineering” makes use of artificially stimulated cell proliferation by using suitable nanomaterial-based scaffolds and growth factors. Tissue engineering might replace today’s conventional treatments like organ transplants or artificial implants. On the other hand, tissue engineering is closely related to the ethical debate on human stem cells and their ethical implications.
Ø Drug Delivery
Researchers are investigating nanoparticles as drug carriers. These nanoscale drug carriers could be coated with nano-sensors, which could recognize diseased tissues and attach to them, releasing a drug exactly where needed. Nanoparticles could also be used to enter damaged cells and release enzymes that tell the cells to auto-destruct, or they could release enzymes to try to repair the cell and return it to normal functioning.
The overall drug consumption and side effects can be lowered significantly by depositing the active agent in the morbid region only and in no higher dose than needed. This highly selective approach reduces costs and human suffering. An example can be found in dendrimers and nanoporous materials. They could hold small drug molecules transporting them to the desired location. Another vision is based on small electromechanical systems; NEMS are being investigated for the active release of drugs. Some potentially important applications include cancer treatment with iron nanoparticles or gold shells. A targeted or personalized medicine reduces drug consumption and treatment expenses resulting in an overall societal benefit by reducing the costs to the public or health system. Nanotechnology is also opening up new opportunities in implantable delivery systems, which are often preferable to the use of injectable drugs because the latter frequently display first-order kinetics (the blood concentration goes up rapidly, but drops exponentially over time). This rapid rise may cause difficulties with toxicity, and drug efficacy can diminish as the drug concentration falls below the targeted range.
A research group headed by Professor A.N. Maitra of the University of Delhi’s Chemistry Department has developed 11 patentable technologies for improved drug delivery systems using nanoparticles. Four of these processes have been granted U.S. patents. One of the important achievements at the initial stage of drug delivery e research was the development of a reverse micelles-based process for the synthesis of hydrogel and smart hydrogen nanoparticles for encapsulating water-soluble drugs. This method enabled one to synthesize hydro gel nanoparticles of size less than 100nm diameter. This technology has been sold to Dabur Research Foundation in 1999.
Another technology has been transferred to the industry dealing with nanoparticle drug delivery for eye diseases. Traditionally, steroids have been used extensively in the treatment of ocular inflammatory disease and allergies. However, prolonged use of steroids has many side effects. The Delhi university group’s process uses nanoparticles to encapsulate non-steroidal drugs.” This process improves the bioavailability of the drug on the surface of the cornea”. The technology has been transferred to Chandigarh-based Panacea Biotech Ltd.
Ø Chemistry and Environment
Chemical catalysis and filtration techniques are two prominent examples where nanotechnology already plays a role. The synthesis provides novel materials with tailored features and chemical properties: for example, nanoparticles with a distinct chemical surrounding (ligands), or specific optical properties. In this sense, chemistry is indeed basic nanoscience. In a short-term perspective, chemistry will provide novel “nanomaterials” and in the long run, superior processes such as “self-assembly” will enable energy and time preserving strategies. In a sense, all chemical synthesis can be understood in terms of nanotechnology, because of its ability to manufacture certain molecules. Thus, chemistry forms a base for nanotechnology providing tailor-made molecules, polymers, etcetera, as well as clusters and nanoparticles.
Ø Catalysis
Chemical catalysis benefits especially from nanoparticles, due to the extremely large surface-to-volume ratio. The application potential of nanoparticles in catalysis ranges from the fuel cells to catalytic converters and photocatalytic devices. Catalysis is also important for the production of chemicals.
Platinum nanoparticles are now being considered in the next generation of automotive catalytic converters because the very high surface area of nanoparticles could reduce the amount of platinum required. However, some concerns have been raised due to experiments demonstrating that they will spontaneously combust methane mixed with the ambient air. Nanofiltration may come to be an important application, although future research must be careful to investigate possible toxicity.
Ø Filtration
A strong influence of nanochemistry on waste-water treatment, air purification, and energy storage devices is to be expected. Mechanical or chemical methods can be used for effective filtration techniques. One class of filtration techniques is based on the use of membranes with suitable hole sizes, whereby the liquid is pressed through the membrane. Nanoporous membranes are suitable for mechanical filtration with extremely small pores smaller than 10 nm (“nanofiltration”) and may be composed of nanotubes. Nanofiltration is mainly used for the removal of ions or the separation of different fluids. On a larger scale, the membrane filtration technique is named ultrafiltration, which works down to between 10 and 100 nm. One important field of application for ultrafiltration is medical purposes as can be found in renal dialysis. Magnetic nanoparticles offer an effective and reliable method to remove heavy metal contaminants from waste water by making use of magnetic separation techniques. Using nanoscale particles increases the efficiency to absorb the contaminants and is comparatively inexpensive compared to traditional precipitation and filtration methods.
Some water-treatment devices incorporating nanotechnology are already on the market, with more in development. Low-cost nanostructured separation membrane methods have been shown to be effective in producing potable water in a recent study.
The scientists from Banaras Hindu University have devised a simple method to produce carbon nanotube filters that efficiently remove micro-to nano-scale contaminants from water and heavy hydrocarbons from petroleum.
Ø Better Air Quality
Nanotechnology can improve the performance of catalysts used to transform vapors escaping from cars or industrial plants into harmless gasses. That’s because catalysts made from nanoparticles have a greater surface area to interact with the reacting chemicals than catalysts made from larger particles. The larger surface area allows more chemicals to interact with the catalyst simultaneously, which makes the catalyst more effective.
Ø Cleaner Water
Nanotechnology is being used to develop solutions to three very different problems in water quality. One challenge is the removal of industrial wastes, such as a cleaning solvent called TCE, from groundwater. Nanoparticles can be used to convert the contaminating chemical through a chemical reaction to make it harmless. Studies have shown that this method can be used successfully to reach contaminates dispersed in underground ponds and at a much lower cost than methods that require pumping the water out of the ground for treatment.
Ø Energy
The most advanced nanotechnology projects related to energy are storage, conversion, manufacturing improvements by reducing materials and process rates, energy saving (by better thermal insulation for example), and enhanced renewable energy sources.
A reduction in energy consumption can be reached by better insulation systems, the use of more efficient lighting or combustion systems, and by use of lighter and stronger materials in the transportation sector. Currently used light bulbs only convert approximately 5% of the electrical energy into light. Nanotechnological approaches like light-emitting diodes (LEDs) or quantum caged atoms (QCAs) could lead to a strong reduction in energy consumption for illumination.
Increasing the Efficiency of Energy Production: Today’s best solar cells have layers of several different semiconductors stacked together to absorb light at different energies but they still only manage to use 40 percent ‘ of the Sun’s energy. Commercially available solar cells have much lower efficiencies (15-20%). Nanotechnology could help increase the efficiency of light conversion by using nanostructures with a continuum of bandgaps. The degree of efficiency of the internal combustion engine is about 30-40% at the moment. Nanotechnology could improve combustion by designing specific catalysts with maximized surface area. In 2005, scientists at the University of Toronto developed a spray-on nanoparticle substance that, when applied to a surface, instantly transforms; into a solar collector.
The Use of More Environmentally Friendly Energy Systems: An example of an environmentally friendly form of energy is the use of fuel cells powered by hydrogen, which is ideally produced by renewable energies, probably the most prominent nanostructured material in fuel cells is the catalyst consisting of carbon-supported noble metal particles with diameters of 1-5 nm. Suitable materials for hydrogen storage contain a large number of mall nanosized pores. Therefore many nanostructured materials like nanotubes, zeolites or alanates are under investigation. Nanotechnology can contribute to the further reduction of combustion engine pollutants by nanoporous filters, which can clean the exhaust mechanically, by catalytic converters based on nanoscale noble metal parties, or by catalytic coatings on cylinder walls and catalytic nanoparticles as additives for fuels.
Recycling of Batteries: Because of the relatively low energy density of batteries the operating time is limited and a replacement or recharging is needed. The huge number of spent batteries and accumulators represent a disposal problem. The use of batteries with higher energy content or the use of rechargeable batteries or supercapacitors with a higher rate of recharging using nanomaterials could be helpful for the battery disposal problem.
Ø Information and Communication
Current high-technology production processes are based on traditional top-down strategies, where nanotechnology has already been introduced silently. The critical length scale of integrated circuits is already at the nanoscale (50 mi and below) regarding the gate length of transistors in CPUs or DRAM devices.
Ø Memory Storage
Electronic memory designs in the past have largely relied on the formation of transistors however research into crossbar switch-based electronics have offered an alternative using reconfigurable interconnections between vertical and horizontal wiring arrays to create ultra-high-density memories. Two leaders in this area are Nantero which has developed a carbon nanotube-based crossbar memory called Nano-RAM and Hewlett-Packard which has proposed the use of memristor material as a future replacement for Flash memory.
Ø Novel Semiconductor Devices
An example of such novel devices is based on spintronics. The dependence of the resistance of a material (due to le spin of the electrons) on an external field is called magnetoresistance. This effect can be significantly amplified 3MR – Giant Magneto-Resistance) for nanosized objects, for example when two ferromagnetic layers are separated by a nonmagnetic layer, which is several nanometers thick (e.g. Co-Cu-Co). The GMR effect has led to a strong increase in the data storage density of hard disks and made the gigabyte range possible. The so-called tunneling magnetoresistance (TMR) is very similar to GMR and based on the spin-dependent tunneling of electrons through adjacent ferromagnetic layers. Both GMR and TMR effects can be used to create a non-volatile main memory for computers, such as the so-called magnetic random access memory or MRAM.
Today it would be impossible to master the coordinated assembly of a large number of these transistors on a circuit and it would also be impossible to create this on an industrial level.
Ø Novel Optoelectronic Devices
In modern communication technology, traditional analog electrical devices are increasingly replaced by optical or optoelectronic devices due to their enormous bandwidth and capacity, respectively. Two promising examples are photonic crystals and quantum dots. Photonic crystals are materials with a periodic variation in the refractive index with a lattice constant that is half the wavelength of the light used. They offer a selectable band gain for the propagation of a certain wavelength, thus they resemble a semiconductor, but for light or photons instead of electrons. Quantum dots are nanoscaled objects, which can be used, among many obi things, for the construction of lasers. The advantage of a quantum dot laser over the traditional semiconductor laser is that its emitted wavelength depends on the diameter of the dot. Quantum dot lasers are cheaper and offer a higher beam quality than conventional laser diodes.
Ø Displays
The production of displays with low energy consumption could be accomplished using carbon nanotubes (CNT), Carbon nanotubes are electrically conductive and due to their small diameter of several nanometers, they can be used as field emitters with extremely high efficiency for field emission displays (FED). The principle of operation resembles that of the cathode ray tube, but on a much smaller length scale.
Ø Quantum Computers
Entirely new approaches for computing exploit the laws of quantum mechanics for novel quantum computers which enable the use of fast quantum algorithms. The Quantum computer will have quantum bit memory space termed qubit for several computations at the same time.
Ø Heavy Industry
An inevitable use of nanotechnology will be in heavy industry.
Ø Aerospace
Lighter and stronger materials will be of immense use to aircraft manufacturers, leading to increased performance. Spacecraft will also benefit, where weight is a major factor. Nanotechnology thereby helps to reduce the size of equipments used.
Hang gliders halve their weight while increasing their strength and toughness through the use of nanotech materials. Nanotech is lowering the mass of super capacitors that will increasingly be used to give power to assistive electrical motors for launching hang gliders off flatland to thermal-chasing altitudes.
Ø Refineries
Using nanotech applications, refineries producing materials such as steel and aluminum will be able to remove any impurities in the materials they create.
Ø Vehicle Manufacturers
Much like aerospace, lighter and stronger materials will be useful for creating vehicles that are both faster and safer. Combustion engines will also benefit from parts that are more hard-wearing and more heat-resistant.
Ø Consumer Goods
Nanotechnology is already impacting the field of consumer goods, providing products with novel functions ranging from easy-to-clean to scratch-resistant. Modern textiles are wrinkle-resistant and stain-repellent; in the mid-term clothes will become “smart”, through embedded “wearable electronics”. Already in use are different nanoparticle-improved products. Especially in the field of cosmetics, such novel products have a promising potential.
Ø Foods
Nanotechnology can be applied in the production, processing, safety, and packaging of food. A nanocomposite coating process could improve food packaging by placing anti-microbial agents directly on the surface of the coated film. Nanocomposites could increase or decrease gas permeability of different fillers as is needed for different products. They can also improve the mechanical and heat-resistance properties and lower the oxygen transmission rate. Research is being performed to apply nanotechnology to the detection of chemical and biological substances for sensing biochemical changes in foods.
Ø Household
The most prominent application of nanotechnology in the household is self-cleaning or “easy-to-clean” surfaces on ceramics or glasses. Nanoceramic particles have improved the smoothness and heat resistance of common household equipment such as the flat iron.
Ø Optics
The first sunglasses using protective and antireflective ultrathin polymer coatings are on the market. For optics, nanotechnology also offers scratch resistant surface coatings based on nanocomposites. Nano-optics could allow for an increase in precision of pupil repair and other types of laser eye surgery.
Ø Textiles
The use of engineered nanofibers already makes clothes water- and stain-repellent or wrinkle-free. Textiles with a nanotechnological finish can be washed less frequently and at lower temperatures. Nanotechnology has been used to integrate tiny carbon particles membrane and guarantee full-surface protection from electrostatic charges for the wearer. Many other applications have been developed by research institutions such as the Textiles Nanotechnology Laboratory at Cornell University
Ø Cosmetics
One field of application is sunscreens. The traditional chemical UV protection approach suffers from its poor long-term stability. A sunscreen based on mineral nanoparticles such as titanium dioxide offers several advantages. Titanium oxide nanoparticles have a comparable UV protection property as the bulk material, but lose the cosmetically undesirable whitening as the particle size is decreased.
Ø Products with Nanotechnology
You might be surprised to find out how many products on the market are already benefiting from nanotechnology.
Sunscreen – Many sunscreens contain nanoparticles of zinc oxide or titanium oxide. Older sunscreen formulas use larger particles, which is what gives most sunscreens their whitish color. Smaller particles are less visible, meaning that when you rub the sunscreen into your skin, it doesn’t give you a whitish tinge.
Self-Cleaning Glass – A company called Pilkington offers a product they call Activ Glass, which uses nanoparticles to make the glass photocatalytic and hydrophilic. The photocatalytic effect means that when UV radiation from light hits the glass, nanoparticles become energized and begin to break down and loosen organic molecules on the glass (in other words, dirt). Hydrophilic means that when water makes contact with the glass, it spreads across the glass evenly, which helps wash the glass clean.
Clothing – Scientists are using nanoparticles to enhance your clothing. By coating fabrics with a thin layer of zinc oxide nanoparticles, manufacturers can create clothes that give better protection from UV radiation. Some clothes have nanoparticles in the form of little hairs or whiskers that help repel water and other materials, making the clothing stain-resistant. Scratch-Resistant Coatings – Engineers discovered that adding aluminum silicate nanoparticles to scratch-resistant polymer coatings made the coatings more effective, increasing resistance to chipping and scratching. Scratch-resistant coatings are common on everything from cars to eyeglass lenses.
Antimicrobial Bandages – Scientist Robert Burrell created a process to manufacture antibacterial bandages using nanoparticles of silver. Silver ions block microbes’ cellular respiration [source: Burnsurgery.org], In other words, silver smothers harmful cells, killing them.
Swimming Pool Cleaners and Disinfectants – Enviro Systems, Inc. developed a mixture (called a nanoemulsion) of nano-sized oil drops mixed with a bactericide. The oil particles adhere to bacteria, making the delivery of the bactericide more efficient and effective.
Ø Nano Technology in Space Science
Advanced miniaturization is a key thrust area to enable new science and exploration missions;
Ultra-small sensors, power sources, communication, navigation, and propulsion systems with every low mass, volume, and power consumption are needed, nanotech would be helpful in relishing these objectives.
Revolutions in electronics and computing will allow reconfigurable, autonomous, thinking spacecraft. Nanotechnology presents whole new spectrum of opportunities to build device components and systems for entirely new space architectures like networks of ultra small probes on planetary surfaces, Micro-rovers, and micro spacecraft, capable of making a variety of measurements.
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