The term nanoparticle is generally used to refer to a small particle with all three dimensions less than 100 nanometres ^[1]. The term also includes subcategories such as nanopowders, nanoclusters and nanocrystals.

A nanocluster is an amorphous/semicrystalline nanostructure with at least one dimension being between 1-10nm and a narrow size distribution.^[2] This distinction is an extension of the term "cluster" which is used in inorganic/organometallic chemistry to indicate small molecular cages of fixed sizes. Look up cluster in Wiktionary, the free dictionary. ...

A nanopowder is an agglomeration of noncrystalline nanostructural subunits with at least one dimension less than 100nm.^[2]

The term nanocrystal is not a generic term. The term is actually a registered trademark of Elan Pharma International (EPIL) used in relation to EPIL’s proprietary milling process and nanoparticulate drug formulations. See for example US TM Reg. Nos. 2386089 / 2492925 and EU CTM Reg. No. 000885079. A nanocrystal is a crystalline material with dimensions measured in nanometers; a nanoparticle with a structure that is mostly crystalline. ...

Nanoparticle research is currently an area of intense scientific research, due to a wide variety of potential applications in biomedical, optical, and electronic fields. The National Nanotechnology Initiative has lead to generous public funding for nanoparticle research in the United States. The National Nanotechnology Initiative is a American federal nanoscale science, engineering, and technology research and development program. ...

History

Although generally nanoparticles are considered an invention of modern science, they actually have a very long history. Specifically, nanoparticles were used by artisans as far back as in the 9th century Mesopotamia for generating a glittering effect on the surface of pottery. An artisan, also called a craftsman,[1] is a skilled manual worker who uses tools and machinery in a particular craft. ... As a means of recording the passage of time the 9th century was the century that lasted from 801 to 900. ... Mesopotamia was a cradle of civilization geographically located between the Tigris and Euphrates rivers, largely corresponding to modern-day Iraq. ... Glitter is the word used to describe an assortment of very small (roughly 1 mm²) pieces of paper, glass or plastic painted in metallic, neon and iridescent colors to reflect light in a sparkling spectrum. ...

Even these days pottery from the Middle Ages and Renaissance often retain a distinct gold or copper colored metallic glitter. This so called lustre is caused by a metallic film that was applied to the transparent surface of a glazing. The lustre can still be visible if the film has resisted atmospheric oxidation and other weathering. Pottery on display in Dilli Haat, Delhi, India. ... The Middle Ages formed the middle period in a traditional schematic division of European history into three ages: the classical civilization of Antiquity, the Middle Ages, and modern times, beginning with the Renaissance. ... This article is about the European Renaissance of the 14th-17th centuries. ... Lustre (American English: luster) is a description of the way light interacts with the surface of a crystal, rock or mineral. ... Glazing, in architecture, is a transparent part of a wall, usually made of glass or plastic (acrylic and polycarbonate). ...

The lustre originates within the film itself, which contains silver and copper nanoparticles, dispersed homogeneously in the glassy matrix of the ceramic glaze. These nanoparticles were created by the artisans by adding copper and silver salts and oxides together with vinegar, ochre, and clay, on the surface of previously-glazed pottery. The object was then placed to a kiln and heated to about 600°C in a reducing atmosphere. For other uses, see Copper (disambiguation). ... This article is about the chemical element. ... This article is about common table salt. ... An oxide is a chemical compound containing at least one oxygen atom and other elements. ... Vinegar is sometimes infused with spices or herbs—as here, with oregano. ... This article is about the color. ... For other uses, see Clay (disambiguation). ... Charcoal Kilns, California Gold Kiln, Victoria, Australia Hop kiln. ... Redox reactions include all chemical processes in which atoms have their oxidation number (oxidation state) changed. ...

In the heat the glaze would soften, causing the copper and silver ions to migrate into the outer layers of the glaze. There the reducing atmosphere reduced the ions back to metals, which then came together forming the nanoparticles that give the colour and optical effects. This article is about the electrically charged particle. ...

Lustre technique shows that craftsmen had a rather sophisticated empirical knowledge of materials. The technique originates in the islamic world. As Muslims were not allowed to use gold in artistic representations, they had to find a way to create a similar effect without using real gold. The solution they found was using lustre. For people named Islam, see Islam (name). ...

Michael Faraday provided the first description, in scientific terms, of the optical properties of nanometer-scale metals in his classic 1857 paper "Experimental relations of gold (and other metals) to light."^[3]

Much of the modern day studies of these objects have been conducted at the ESRF laboratory. Several techniques were used to characterise the chemical and physical properties of these lustre, such as Rutherford Backscattering Spectrometry (RBS), optical absorption in the visible-ultraviolet region, electron microscopy (TEM and SEM), X-ray diffraction and X-ray absorption spectroscopy.^[4] ESRF site ESRF redirects here, for the medical condition, see end stage renal failure The European Synchrotron Radiation Facility is a joint research facility supported by 18 European countries situated in Grenoble, France. ... Rutherford backscattering spectroscopy (RBS) is an analytical technique used in materials science. ... For other uses, see Ultraviolet (disambiguation). ... The electron microscope is a microscope that can magnify very small details with high resolving power due to the use of electrons rather than light to scatter off material, magnifying at levels up to 500,000 times. ... Transmission electron microscopy (TEM) is an imaging technique whereby a beam of electrons is focused onto a specimen causing an enlarged version to appear on a fluorescent screen or layer of photographic film (see electron microscope), or can be detected by a CCD camera. ... SEM Cambridge S150 at Geological Institute, University Kiel, 1980 SEM opened sample chamber The scanning electron microscope (SEM) is a type of electron microscope capable of producing high-resolution images of a sample surface. ... X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of x-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. ... The X-ray Absorption Spectroscopy is currently a widely used technique giving information on the local structure and on the electronic states in gas-phase, molecular and condensed matter. ...

Properties

Silicon nanopowder

Nanodiamonds, TEM image

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 this is often not the case. Size-dependent properties are observed such as quantum confinement in semiconductor particles, surface plasmon resonance in some metal particles and superparamagnetism in magnetic materials. Image File history File linksMetadata Nano_Si_640x480. ... Image File history File linksMetadata Nano_Si_640x480. ... Image File history File links Nanodiamonds. ... Image File history File links Nanodiamonds. ... The general meaning of atomic is irreducible. That is, reduced to the smallest possible part. ... In science, a molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. ... A potential well is the region surrounding a local minimum of potential energy. ... A semiconductor is a solid material that has electrical conductivity in between that of a conductor and that of an insulator; it can vary over that wide range either permanently or dynamically. ... The excitation of surface plasmons by light is denoted as a surface plasmon resonance (SPR) for planar surfaces or localized surface plasmon resonance (LSPR) for nanometer-sized metallic structures. ... Superparamagnetism refers to materials which become magnetic in the presence of an external magnet, but revert to a non magnetic state when the external magnet is removed. ... In physics, magnetism is a phenomenon by which materials exert an attractive or repulsive force on other materials. ...

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 micrometre the percentage of atoms at the surface is minuscule relative to the total number of atoms of the material. The interesting and sometimes unexpected properties of nanoparticles are partly due to the aspects of the surface of the material dominating the properties in lieu of the bulk properties.

Nanoparticles exhibit a number of special properties relative to bulk material. For example, the bending of bulk copper (wire, ribbon, etc.) occurs with movement of copper atoms/clusters at about the 50 nm scale. Copper nanoparticles smaller than 50 nm are considered super hard materials that do not exhibit the same malleability and ductility as bulk copper. The change in properties is not always desirable. Ferroelectric materials smaller than 10 nm can switch their magnetisation direction using room temperature thermal energy, thus making them useless for memory storage. Suspensions of nanoparticles are possible because the interaction of the particle surface with the solvent is strong enough to overcome differences in density, which usually result in a material either sinking or floating in a liquid. Nanoparticles often have unexpected visible properties because they are small enough to confine their electrons and produce quantum effects. For example gold nanoparticles appear deep red to black in solution. For other uses, see Copper (disambiguation). ... Look up malleability in Wiktionary, the free dictionary. ... Gold is a highly ductile metal Ductility is a mechanical property which describes how much plastic deformation a material can sustain before fracture occurs. ... It has been suggested that this article or section be merged into Mixture. ... For other uses, see Solvent (disambiguation). ... For other uses, see Density (disambiguation). ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ...

Nanoparticles have a very high surface area to volume ratio. This provides a tremendous driving force for diffusion, especially at elevated temperatures. Sintering can take place at lower temperatures, over shorter time scales than for larger particles. This theoretically does not affect the density of the final product, though flow difficulties and the tendency of nanoparticles to agglomerate complicates matters. The large surface area to volume ratio also reduces the incipient melting temperature of nanoparticles ^[5]. diffusion (disambiguation). ... This article or section does not cite its references or sources. ... For other uses, see Density (disambiguation). ...

Moreover nanoparticles have been found to impart some extra properties to various day to day products. Like the presence of titanium dioxide nanoparticles impart what we call as the self-cleaning effect, and the size being nanorange, the particles cant be seen. Nano Zinc Oxide particles have been found to have superior UV blocking properties compared to its bulk substitute. This is one of the reasons why it is often used in the sunscreen lotions. Clay nanoparticles when incorporated into polymer matrices increase re-inforcement, leading to stronger plastics, verified by a higher glass transition temperature and other mechanical property tests. These nanoparticles are hard, and impart their properties to the polymer (plastic).

Classification

At the small end of the size range, nanoparticles are often referred to as clusters. Nanospheres, nanorods, and nanocups are just a few of the shapes that have been grown. In physics, the term clusters denotes small, multiatom particles. ... In nanotechnology, nanorods are one morphology of nanoscale objects. ...

Metal, dielectric, and semiconductor nanoparticles have been formed, as well as hybrid structures (e.g., core-shell nanoparticles). Nanoparticles made of semiconducting material may also be labeled quantum dots if they are small enough (typically sub 10 nm) that quantization of electronic energy levels occurs. Such nanoscale particles are used in biomedical applications as drug carriers or imaging agents. This article is about metallic materials. ... A dielectric is a nonconducting substance, i. ... A semiconductor is a solid material that has electrical conductivity in between that of a conductor and that of an insulator; it can vary over that wide range either permanently or dynamically. ... For other uses, see Resonance (disambiguation). ... A quantum dot is a potential well that confines electrons in three dimensions to a region of the order of the electrons de Broglie wavelength in size, a few nanometers in a semiconductor. ... Look up quantization in Wiktionary, the free dictionary. ... A quantum mechanical system can only be in certain states, so that only certain energy levels are possible. ... Drug carriers are substances that serve as mechanisms to improve the delivery and the effectiveness of drugs. ... Imaging agents are chemicals designed to allow clinicians to determine whether a mass is benign or malignant and locate metastatic cancer sites in the body. ...

Semi-solid and soft nanoparticles have been manufactured. A prototype nanoparticle of semi-solid nature is the liposome. Various types of liposome nanoparticles are currently used clinically as delivery systems for anticancer drugs and vaccines. A liposome is a spherical vesicle with a membrane composed of a phospholipid and cholesterol bilayer. ... A liposome is a spherical vesicle with a membrane composed of a phospholipid and cholesterol bilayer. ...

Characterization

Nanoparticle characterization is necessary to establish understanding and control of nanoparticle synthesis and applications. Characterization is done by using a variety of different techniques, mainly drawn from materials science. Common techniques are electron microscopy [TEM,SEM], atomic force microscopy [AFM], dynamic light scattering [DLS], x-ray photoelectron spectroscopy [XPS], powder x-ray diffractometry [XRD], Fourier transform infrared spectroscopy [FTIR], Matrix-Assisted Laser-Desorption Time-of-flight mass spectrometry [MALDI-TOF], and Ultraviolet-visible spectroscopy. The Materials Science Tetrahedron, which often also includes Characterization at the center Materials science or Materials Engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering. ... The electron microscope is a microscope that can magnify very small details with high resolving power due to the use of electrons rather than light to scatter off material, magnifying at levels up to 500,000 times. ... The atomic force microscope (AFM) is a very powerful microscope invented by Binnig, Quate and Gerber in 1986. ... Dynamic light scattering is a powerful technique in physics, which can be used to determine the size distribution profile of small particles in solution. ... Basic components of a monochromatic XPS system. ... X-ray crystallography, also known as single-crystal X-ray diffraction, is the oldest and most common crystallographic method for determining the structure of molecules. ... FTIR of a thin film of ethanol in the liquid phase. ... Matrix-Assisted Laser Desorption/Ionization (MALDI) is a soft ionization technique used in mass spectrometry, allowing, among others, to ionize biomolecules (biopolymers like proteins, peptides and sugarchains) which tend to be more fragile and quickly lose structure when ionized by more conventional ionization methods. ... This article is about the mass spectrometry technique. ...

Whilst the theory has been known for over a century (see Robert Brown), the technology for Nanoparticle tracking analysis (NTA) allows direct tracking of the Brownian motion and this method therefore allows the sizing of individual nanoparticles in solution. Robert Brown can refer to: Sir Robert Brown, 1st Baronet, of Westminster (died 1760), British Member of Parliament Robert (Bob) Brown (born 1944), Australian Greens senator Robert Brown (Australian Labor politician), Australian politician from 1978 to 1998 Robert Brown (Australian Shooters Party politician), Australian politician since 2006 Robert Brown (English... Nanoparticle Tracking Analysis is a technique developed by nanosight which allows nano-particles (smaller than the wave length of light) to be seen via a microscope. ... Three different views of Brownian motion, with 32 steps, 256 steps, and 2048 steps denoted by progressively lighter colors. ...

Fabrication of nanoparticles

There are several methods for creating nanoparticles; attrition and pyrolysis are common methods. In attrition, macro or micro scale particles are ground in a ball mill, a planetary ball mill, or other size reducing mechanism. The resulting particles are air classified to recover nanoparticles. Attrition means wearing down by friction or grinding and may refer to the following. ... Simple sketch of pyrolysis chemistry Pyrolysis usually means the chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents, except possibly steam. ... A ball mill, a type of crusher, is a cylindrical device used to grind (or mix) materials like ores, chemicals, ceramics and paints. ...

In pyrolysis, an organic precursor (liquid or gas) is forced through an orifice at high pressure and burned. The resulting ash is air classified to recover oxide nanoparticle.

A thermal plasma can also deliver the energy necessary to cause evaporation of small micrometre size particles. The thermal plasma temperatures are in the order of 10000 K, so that solid powder easily evaporates. Nanoparticles are formed upon cooling while exiting the plasma region. The main types of the thermal plasmas torches used to produce nanoparticles are dc plasma jet, dc arc plasma and radio frequency (RF) induction plasmas. In the arc plasma reactors, the energy necessary for evaporation and reaction is provided by an electric arc which forms between the anode and the cathode. For example, silica sand can be vaporized with an arc plasma at atmospheric pressure. The resulting mixture of plasma gas and silica vapour can be rapidly cooled by quenching with oxygen, thus ensuring the quality of the fumed silica produced. In RF induction plasma torches, energy coupling to the plasma is accomplished through the electromagnetic field generated by the induction coil. The plasma gas does not come in contact with electrodes, thus eliminating possible sources of contamination and allowing the operation of such plasma torches with a wide range of gases including inert, reducing, oxidizing and other corrosive atmospheres. The working frequency is typically between 200 kHz and 40 MHz. Laboratory units run at power levels in the order of 30-50 kW while the large scale industrial units have been tested at power levels up to 1 MW. As the residence time of the injected feed droplets in the plasma is very short it is important that the droplet sizes are small enough in order to obtain complete evaporation. The RF plasma method has been used to synthesize different nanoparticle materials, for example synthesis of various ceramic nanoparticles such as oxides, carbours/carbides and nitrides of Ti and Si.

Inert-gas aggregation is frequently used to make nanoparticles from metals with low melting points. The metal is vaporized in a vacuum chamber and then supercooled with an inert gas stream. The supercooled metal vapor condenses in to nanometer-sized particles, which can be entrained in the inert gas stream and deposited on a substrate or studied in situ.

Nanoparticle Morphology

Nanostars of Vanadium(IV) oxide

Scientists have taken to naming their particles after the real world shapes that they might represent. Nanospheres^[6], nanoreefs ^[7], nanoboxes ^[8] and more have appeared in the literature. These morphologies sometimes arise spontaneously as an effect of a templating or directing agent present in the synthesis such as micellular emulsions or anodized alumina pores, or from the innate crystallographic growth patterns of the materials themselves. ^[9] Some of these morphologies may serve a purpose, such as long carbon nanotubes being used to bridge an electrical junction, or just a scientific curiosity like the stars shown at left. Vanadium(IV) oxide Categories: | | ... // 3D model of three types of single-walled carbon nanotubes. ...

Safety Issues

See also: Nanotoxicology  and Fine particles

Nanoparticles present possible dangers, both medically and environmentally.^[10] Most of these are due to the high surface to volume ratio, which can make the particles very reactive or catalytic.^[11] They are also able to pass through cell membranes in organisms, and their interactions with biological systems are relatively unknown.^[12] However, free nanoparticles in the environment quickly tend to agglomerate and thus leave the nano-regime, and nature itself presents many nanoparticles to which organisms on earth may have evolved immunity (such as salt particulates from ocean aerosols, terpenes from plants, or dust from volcanic eruptions)^{[citation needed]}. A fuller analysis is provided in the article on nanotechnology. Research on ultrafine particles has laid the foundation for the emerging field of nanotoxicology, with the goal of studying the biokinetics of engineered nanomaterials and their potential for causing adverse effects. ... Fine particles Fine particles is an air pollutant mainly produced by cars running on diesel. ... In chemistry and biology, catalysis (in Greek meaning to annul) is the acceleration of the rate of a chemical reaction by means of a substance, called a catalyst, that is itself unchanged chemically by the overall reaction. ... The cell membrane (also called the plasma membrane, plasmalemma or phospholipid bilayer) is a selectively permeable lipid bilayer found in all cells. ... This article or section does not adequately cite its references or sources. ... Animated map exhibiting the worlds oceanic waters. ... Aerosol, is a term derived from the fact that matter floating in air is a suspension (a mixture in which solid or liquid or combined solid-liquid particles are suspended in a fluid). ... Many terpenes are derived from conifer resins, here a pine. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... Nanotechnology refers to a field of applied science and technology whose theme is the control of matter on the atomic and molecular scale, generally 100 nanometers or smaller, and the fabrication of devices that lie within that size range. ...

According to the San Francisco Chronicle, "Animal studies have shown that some nanoparticles can penetrate cells and tissues, move through the body and brain and cause biochemical damage. But whether cosmetics and sunscreens containing nanomaterials pose health risks remains largely unknown, pending completion of long-range studies recently begun by the FDA and other agencies."^[13] Diesel nanoparticles have been found to damage the cardiovascular system in a mouse model.^[14] Todays San Francisco Chronicle was founded in 1865 as The Daily Dramatic Chronicle by teenage brothers Charles de Young and Michael H. de Young. ...

See also

Wikibooks has a book on the topic of

Nanotechnology

• Quantum dot
• Nanocrystalline silicon
• Photonic crystal
• Nanotechnology
• Nanobiotechnology
• Liposome
• Nanomaterials
• Nanoparticle Tracking Analysis
• Silver Nano

Image File history File links Wikibooks-logo-en. ... Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a wiki for the creation of books. ... Colloidal quantum dots irradiated with a UV light. ... Silicon nanopowder Nanocrystalline silicon (nc-Si) - an allotropic form of silicon - is similar to amorphous silicon (a-Si), in that it has an amorphous phase. ... The opal in this bracelet contains a natural periodic microstructure responsible for its iridescent color. ... Nanotechnology refers to a field of applied science and technology whose theme is the control of matter on the atomic and molecular scale, generally 100 nanometers or smaller, and the fabrication of devices that lie within that size range. ... Nanobiotechnology is the branch of nanotechnology with biological and biochemical applications or uses. ... A liposome is a spherical vesicle with a membrane composed of a phospholipid and cholesterol bilayer. ... Nanomaterials is the study of how materials behave when their dimensions are reduced to the nanoscale. ... Nanoparticle Tracking Analysis is a technique developed by nanosight which allows nano-particles (smaller than the wave length of light) to be seen via a microscope. ...

References

The Royal Society of London is claimed to be the oldest learned society still in existence and was founded in 1660. ... July is the seventh month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... ESRF site ESRF redirects here, for the medical condition, see end stage renal failure The European Synchrotron Radiation Facility is a joint research facility supported by 18 European countries situated in Grenoble, France. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 209th day of the year (210th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Todays San Francisco Chronicle was founded in 1865 as The Daily Dramatic Chronicle by teenage brothers Charles de Young and Michael H. de Young. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 110th day of the year (111th in leap years) in the Gregorian calendar. ...

External Links

• A wide variety of nanoparticles and their dispersions are commercially available from Nanostructured & Amorphous Materials, Inc.
• Nano Particle sized Oxide Powders tested and produced. by Nano-Oxides, Inc.
• International Liposome Society
• Assessing health risks of nanoparticles summary by GreenFacts of the European Commission SCENIHR assessment
• IOP.org Article
• Nano Structured Material

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