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Nano manufacturing is a term used to describe either the production of nano scaled materials, which can be powders or fluids, or to describe the manufacturing of parts "bottom up" from nano scaled materials or "top down" in smallest steps for high precision, used in several technologies such as laser ablation, etching and others. Nano manufacturing should not be confused with molecular manufacturing, which refers specifically to the manufacture of complex, nano scale structures by means of non biological mechanic synthesis (and subsequent assembly).
The term "nano manufacturing" is widely used, e.g. by the European Technology Platform MINAM and the U.S. National Nanotechnology Initiative (NNI). The NNI refers to the sub-domain of nanotechnology as one of its five "priority areas." There is also a nano manufacturing program at the U.S. National Science Foundation, through which the National Nano manufacturing Network (NNN) has been established. The NNN is an organization that works to expedite the transition of nanotechnologies from laboratory research to production manufacturing and it does so through information exchange, strategic workshops, and roadmap development.
The NNI has defined nanotechnology very broadly, to include a wide range of tiny structures, including those created by large and imprecise tools. However, nano manufacturing is not defined in the NNI's recent report, Instrumentation and Metrology for Nanotechnology. In contrast, another "priority area," nanofabrication, is defined as "the ability to fabricate, by directed or self-assembly methods, functional structures or devices at the atomic or molecular level". Nano manufacturing appears to be the near-term, industrial-scale manufacture of nanotechnology-based objects, with emphasis on low cost and reliability.
Many professional societies have formed Nanotechnology technical groups. The Society of Manufacturing Engineers, for example, has formed a Nano manufacturing Technical Group to both inform members of the developing technologies and to address the organizational and IP (intellectual property) legal issues that must be addressed for broader commercialization.
What is Nanotechnology ?
Nanotechnology, shortened to "nanotech", is the study of the controlling of matter on an atomic and molecular scale. Generally nanotechnology deals with structures of the size 100 nanometers or smaller in at least one dimension, and involves developing materials or devices within that size. Nanotechnology is very diverse, ranging from extensions of conventional device physics to completely new approaches based upon molecular self-assembly, from developing new materials with dimensions on the nano scale to investigating whether we can directly control matter on the atomic scale.
Nanotechnology is not just the miniaturization of technologies-materials at the nanoscale differ significantly from bulk materials in terms of surface area and quantum effects. These differences result in nanomaterials exhibiting mechanical, chemical, electrical, thermal, and biological properties that are unique compared to those of bulk materials. These exceptional properties have the potential to be integrated into innovative products and processes that can dramatically change the way things work.
Nanotechnology has the potential to create many new materials and devices with a vast range of applications, such as in medicine, electronics and energy production. On the other hand, nanotechnology raises many of the same issues as with any introduction of new technology, including concerns about the toxicity and environmental impact of nanomaterials, and their potential effects on global economics, as well as speculation about various doomsday scenarios. These concerns have led to a debate among advocacy groups and governments on whether special regulation of nanotechnology is warranted.
Nano manufacturing is the use of nanotechnology to develop processes and products, whether it is the production of nanomaterials, the fabrication of products that integrate nanomaterials or nanoscale features, or the use of nano-enabled processes to create other products. Projected by many visionary leaders as the "industrial revolution of the 21st century," nano manufacturing is primed to change markets, industries, and business models worldwide.
LIST OF NANOTECHNOLOGY APPLICATIONS
With nanotechnology, a large set of materials and improved products rely on a change in the physical properties when the feature sizes are shrunk. Nanoparticles, for example, take advantage of their dramatically increased surface area to volume ratio. 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 nano technologically enhanced materials will enable a weight reduction accompanied by an increase in stability and improved functionality. Practical nanotechnology is essentially the increasing ability to manipulate (with precision) matter on previously impossible scales, presenting possibilities which many could never have imagined - it therefore seems unsurprising that few areas of human technology are exempt from the benefits which nanotechnology could potentially bring.
Few of the major application of nanotech are:-
In Medicine:- The biological and medical research communities have exploited the unique properties of nano materials for various applications (e.g., contrast agents for cell imaging and therapeutics for treating cancer). Nanotechnology has been a boom in medical field by delivering drugs to specific cells using nanoparticles. 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.
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.
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.
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 nm and below) regarding the gate length of transistors in CPUs or DRAM devices.
In Aircraft Industries:- 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 would help to reduce the size of equipment and thereby decrease fuel-consumption required to get it airborne.
Nano Foods:- Complex set of engineering and scientific challenges in the food and bio processing industry for manufacturing high quality and safe food through efficient and sustainable means can be solved through nanotechnology.
Textiles and Cosmetics:- 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 and the traditional chemical UV protection approach suffers from its poor long-term stability. A sunscreen based on mineral nanoparticles such as titanium dioxide offer 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.
Energy and Environmental Contribution
Nano manufacturing is expected to contribute to the success of the nation's major energy and environmental initiatives. Many of the envisioned nano manufactured goods will use energy more efficiently, produce other goods with far lesser energy consumption, or convert, store, and deliver energy more effectively. It is anticipated that nanotechnology will enable solar cells that are produced at reduced costs and provide higher efficiency; light-weight transportation components that improve fuel economy in automobiles and trucks; more efficient lighting (i.e. LEDs) at homes and offices; and better performing catalysts/separations/materials technologies that enhance the energy efficiency of manufacturing.
The impact from these products and processes will translate directly into large-scale energy savings and reductions in CO2 emissions. The potential for nanorelated energy developments has led Morgan Stanley to describe nanotechnology as the most promising technology for driving "game changing" advances in renewable energy and energy-use technologies.
The implications of nanotechnology run the gamut of human affairs from the medical, ethical, mental, legal and environmental, to fields such as engineering, biology, chemistry, computing, materials science, military applications, and communications.
Benefits of nanotechnology include improved manufacturing methods, water purification systems, energy systems, physical enhancement, nanomedicine, better food production methods and nutrition and large scale infrastructure auto-fabrication. Products made with nanotechnology may require little labor, land, or maintenance, be highly productive, low in cost, and have modest requirements for materials and energy.
Nanomaterials is a field which takes a materials science-based approach to nanotechnology. It studies materials with morphological features on the nanoscale, and especially those which have special properties stemming from their nanoscale dimensions. Nanoscale is usually defined as smaller than a one tenth of a micrometer in at least one dimension, though this term is sometimes also used for materials smaller than one micrometer.
The chemical processing and synthesis of high performance technological components for the private, industrial and military sectors requires the use of high purity ceramics, polymers, glass-ceramics and material composites. In condensed bodies formed from fine powders, the irregular sizes and shapes of nanoparticles in a typical powder often lead to non-uniform packing morphologies that result in packing density variations in the powder compact.
Uncontrolled agglomeration of powders due to attractive van der Waals forces can also give rise to in microstructural in homogeneities. Differential stresses that develop as a result of non-uniform drying shrinkage are directly related to the rate at which the solvent can be removed, and thus highly dependent upon the distribution of porosity. Such stresses have been associated with a plastic-to-brittle transition in consolidated bodies, and can yield to crack propagation in the unfired body if not relieved.
Fig:- A Colloidal crystal composed of amorphous hydrated colloidal silica (particle diameter 600 nm)
CLASSIFICATION OF NANOMATERIALS:-
Materials referred to as "nanomaterials" generally fall into two categories: fullerenes, and inorganic nanoparticles.
The fullerenes are a class of allotropes of carbon which conceptually are graphene sheets rolled into tubes or spheres. These include the carbon nanotubes (or silicon nanotubes) which are of interest both because of their mechanical strength and also because of their electrical properties. A common method used to produce fullerenes is to send a large current between two nearby graphite electrodes in an inert atmosphere. The resulting carbon plasma arc between the electrodes cools into sooty residue from which many fullerenes can be isolated.
In nanotechnology, a particle is defined as a small object that behaves as a whole unit in terms of its transport and properties. It is further classified according to size: in terms of diameter, fine particles cover a range between 100 and 2500 nanometers, while ultrafine particles, on the other hand, are sized between 1 and 100 nanometers. Similar to ultrafine particles, nanoparticles are sized between 1 and 100 nanometers. Nanoparticles may or may not exhibit size-related properties that differ significantly from those observed in fine particles or bulk materials. Although the size of most molecules would fit into the above outline, individual molecules are usually not referred to as nanoparticles.
Properties of Nanoparticles:-
Nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic or molecular structures. A bulk material should have constant physical properties regardless of its size, but at the nano-scale size-dependent properties are often observed. Thus, the properties of materials change as their size approaches the nanoscale and as the percentage of atoms at the surface of a material becomes significant. For bulk materials larger than one micrometer (or micron), the percentage of atoms at the surface is insignificant in relation to the number of atoms in the bulk of the material. The interesting and sometimes unexpected properties of nanoparticles are therefore largely due to the large surface area of the material, which dominates the contributions made by the small bulk of the material.
For example, nanoparticles of usually yellow gold and gray silicon are red in color; gold nanoparticles melt at much lower temperatures (~300 Â°C for 2.5Â nm size) than the gold slabs (1064 Â°C); and absorption of solar radiation in photovoltaic cells is much higher in materials composed of nanoparticles than it is in thin films of continuous sheets of material - the smaller the particles, the greater the solar absorption.
SOME NANOTECH PRODUCTS:-
Nanotech ski wax
Athlete skin care
Exercise equipments etc.
Many optimists people, including many governments, see nanotechnology delivering benefits such as:
environmentally benign material abundance for all by providing universal clean water supplies
atomically engineered food and crops resulting in greater agricultural productivity with fewer labour requirements
Nutritionally enhanced interactive 'smart' foods.
cheap and powerful energy generation
clean and highly efficient manufacturing
radically improved formulation of drugs, diagnostics and organ replacement
much greater information storage and communication capacities
interactive 'smart' appliances; and increased human performance through convergent technologies
Fig: - New Class of Nano-Fibers
Risks include environmental, health, and safety issues if negative effects of nanoparticles are overlooked before they are released; transitional effects such as displacement of traditional industries as the products of nanotechnology become dominant; military applications such as biological warfare and implants for soldiers; and surveillance through nano-sensors, which are of concern to privacy rights advocates.
Potential risks of nanotechnology can broadly be grouped into four areas:
Health issues - the effects of nanomaterials on human biology
Environmental issues - the effects of nanomaterials on the environment
Societal issues - the effects that the availability of nanotechnological devices will have on politics and human interaction
The mere presence of nanomaterials (materials that contain nanoparticles) is not in itself a threat. It is only certain aspects that can make them risky, in particular their mobility and their increased reactivity. Only if certain properties of certain nanoparticles were harmful to living beings or the environment would we be faced with a genuine hazard. In this case it can be called nanopollution.
Now Nanopollution is a generic name for all waste generated by nanodevices or during the nanomaterials manufacturing process. This kind of waste may be very dangerous because of its size. It can float in the air and might easily penetrate animal and plant cells causing unknown effects. Most human-made nanoparticles do not appear in nature, so living organisms may not have appropriate means to deal with nanowaste.
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 other nucleic acids. Approaches from the field of "classical" chemical synthesis also aim at designing molecules with well-defined shape (e.g. bis-peptides).
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.
2. 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 100Â 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 for their discovery of Giant magnetoresistance and contributions to the field of spintronics in 2007.
Focused ion beams can directly remove material, or even deposit material when suitable pre-cursor gasses are applied at the same time. For example, this technique is used routinely to create sub-100Â nm sections of material for analysis in Transmission electron microscopy.