Nanochemistry - archive of the Gordon program. Basic directions and concepts of nanochemistry Nanochemistry and nanotechnology

Nanochemistry is a branch of chemistry that studies the properties, structure and features of chemical transformations of nanoparticles. A distinctive feature of nanochemistry is the presence of a size effect - a qualitative change in physicochemical properties and reactivity when the number of atoms or molecules in a particle changes. Typically, this effect is observed for particles smaller than 10 nm, although this value has a conditional value.

Directions of research in nanochemistry

Development of methods for assembling large molecules from atoms using nanomanipulators; study of intramolecular rearrangements of atoms under mechanical, electrical and magnetic influences.

Synthesis of nanostructures in supercritical fluid flows; development of methods for targeted assembly of nanocrystals.

Development of the theory of physico-chemical evolution of ultradisperse substances and nanostructures; creating ways to prevent chemical degradation of nanostructures.

Obtaining new catalysts for the chemical and petrochemical industries; studying the mechanism of catalytic reactions on nanocrystals.

Study of nanocrystallization mechanisms in porous media in acoustic fields; synthesis of nanostructures in biological tissues.

Study of the phenomenon of self-organization in collectives of nanocrystals; search for new ways to prolong the stabilization of nanostructures with chemical modifiers.

The goal of the research is to develop a functional range of machines that provide:

New catalysts for the chemical industry and laboratory practice.

Methodology for preventing chemical degradation of technical nanostructures; methods for predicting chemical degradation.

Getting new medications.

A method for treating oncological diseases by performing intratumoral nanocrystallization and applying an acoustic field.

New chemical sensors; methods for increasing sensor sensitivity.

Nanotechnology in energy and chemical industry

Nanotechnology (Greek nanos - “dwarf” + “techno” - art, + “logos” - teaching, concept) is an interdisciplinary field of fundamental and applied science and technology, dealing with innovative methods (in the areas of theoretical justification, experimental methods of research, analysis and synthesis, as well as in the field of new industries) obtaining new materials with specified desired properties. Nanotechnology uses the latest technologies for manipulating single atoms or molecules (movement, rearrangements, new combinations). A variety of methods are used (mechanical, chemical, electrochemical, electrical, biochemical, electron beam, laser) for the artificial organization of a given atomic and molecular structure of nanoobjects.

Nanotechnology in energy

Nanotechnologies in the field of energy and mechanical engineering

In this area, the development of science and technology is proceeding in two directions:

1- creation of structural materials,

2- surface nanoengineering

Creation of structural materials,

To create fundamentally new structural materials with the inclusion of ultradisperse (or nanodisperse) elements, we followed the following path. The first is the addition of ultrafine elements as alloying additives. For structural materials in mechanical engineering and energy, fullerenes are exotic and very expensive. The second direction is the creation of ultradisperse systems (UDS) of non-metallic inclusions in steels and alloys, carried out through thermoplastic, thermal or plastic deformation. It turned out that the performance properties of structural materials can be controlled not only by introducing alloying components, which, according to metallurgists, have almost been exhausted, but also by using deformation of any nature. With this effect, non-metallic inclusions are crushed. Traditional annealing and tempering are nothing more than nanotechnology in metallurgy.

As a result of such influences, it is possible to obtain steels (nitrogen steels in Prometheus) in which high strength is combined with ductility, that is, precisely those properties that are lacking in the energy sector, in mechanical engineering, to obtain materials with given characteristics. Nanotechnology makes it possible to successfully obtain such materials.

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MINISTRY OF EDUCATION AND SCIENCE OF THE RUSSIAN FEDERATION

Federal State Educational Institution of Higher Education

"Magnitogorsk State Technical University named after. G.I. Nosov"

Department of Physical Chemistry and Chemical Technology

in the discipline "History of Chemistry and Chemical Technology"

on the topic "Nanochemistry"

Performer: Ksenia Olegovna Perevalova, 2nd year student, group ZTHB-15.1

Head: Ponurko Irina Vitalievna, associate professor, candidate of technical sciences, associate professor

Magnitogorsk, 2017

Introduction

2. Basic concepts of nanoscience

Conclusion

List of sources used

Introduction

In the history of human development, several important historical stages can be identified related to the development of new materials and technologies.

Today, science has come close to the possibility of direct influence on individual atoms and molecules, which has created a fundamentally new development trend, collectively called nanotechnology. The creation and research of structures and objects with controlled parameters and specified properties at the nanoscale is one of the most important technological problems of our time. This is due to the unique properties of materials in a nanostructured state, close to fundamental limitations, the possibility of creating “smart” materials with predetermined programmable properties, the development of new technologies for processing materials and modifying their surface, with the general trend towards miniaturization of products, the creation of fundamentally new objects , devices and even new industries.

Nanotechnologies represent a wide range of scientific, technological and industrial areas, united into a single technological culture based on operations with matter at the level of individual atoms and molecules. We are talking not just about new technologies, but about processes that will change all segments of industry and areas of human activity, including the information environment, healthcare, the economy, and the social sphere.

The introduction of nanotechnology requires the creation of new approaches to engineering education and adaptation to new ideas.

This study examines the main aspects of nanotechnology.

1. History of the formation of nanoscience

The prehistory of modern nanotechnology is connected with centuries-old research efforts of scientists from many countries of the world and has its own long historical trail. Let's look at the most significant stages.

1661 Irish physicist and chemist R. Boyle, one of the founders of the Royal Society of London, in his work “The Skeptical Chemist” pointed out the potential importance of the smallest particles - clusters (“corpuscles”).

Criticizing Aristotle's view of matter consisting of four fundamental principles (earth, fire, water and air), the author suggested that all material objects consist of ultra-small corpuscles that are quite stable and form various substances and objects in different combinations.

Subsequently, the ideas of Democritus and Boyle were accepted by the scientific community.

1857 The English physicist M. Faraday, the founder of the doctrine of the electromagnetic field, was the first to obtain stable colloidal solutions of gold (liquid systems with tiny particles of the dispersed phase, moving freely and independently of each other in the process of Brownian motion). Subsequently, colloidal solutions began to be widely used for the formation of nanosystems.

1861 English chemist T. Graham introduced the division of substances according to the degree of dispersion of the structure into colloidal (amorphous) and crystalloid (crystalline).

An example of the first use of nanotechnology can be considered the invention in 1883 by the American inventor D. Eastman, founder of the famous company Kodak, of a roll of photographic film, which is an emulsion of silver halide applied to a transparent elastic base (for example, from cellulose acetate), which decomposes under the influence of light to form nanoparticles pure silver, which are the pixels of the image.

1900 German physicist M. Planck introduced the concept of quantum of action (Planck's constant) - the starting point for quantum theory, the provisions of which are essential in describing the behavior of nanosystems.

1905 The first scientist to use measurements in nanometers is considered to be the famous physicist A. Einstein, who theoretically proved that the size of a sugar molecule is equal to one nanometer (10 -9 m).

1924 French physicist Louis de Broglie put forward the idea of ​​the wave properties of matter, thereby laying the foundation for quantum mechanics, which studies the movement of microparticles. The laws of quantum mechanics are especially relevant when creating nanoscale structures.

1931 German physicists M. Knoll and E. Ruska created an electron transmission microscope, which became the prototype of a new generation of devices that made it possible to look into the world of nanoobjects.

1939 Siemens released the first industrial electron microscope with ? 10 nm.

1959 American physicist, Nobel laureate R. Feynman, in a famous lecture at the California Institute of Technology, known as “There's Plenty of Room at the Bottom,” expressed ideas for controlling the structure of matter at the atomic level: “By learning to regulate and control structures at the atomic level, we will obtain materials with completely unexpected properties and discover completely unusual effects.

The development of manipulation techniques at the atomic level will solve many problems.” This lecture became, in a sense, a launching pad for nanoresearch. Many visionary ideas expressed by R. Feynman that seemed fantastic (about engraving lines several atoms wide using an electron beam, about manipulating individual atoms to create new small structures, about creating electrical circuits on a nanometer scale, about using nanostructures in biological systems) are today have already been implemented.

1966 American physicist R. Young, who worked at the National Bureau of Standards, invented the piezo motor, which is used today in scanning probe microscopes for precise positioning of nanoinstruments.

1968 Employees of the scientific division of the American company Bell A. Cho and D. Arthur developed the theoretical foundations of surface nanotreatment.

1971 The Bell and IBM companies produced the first semiconductor films of monatomic thickness - quantum wells, which marked the beginning of the era of “practical” nanotechnology.

R. Young put forward the idea of ​​​​the Topografiner device, which served as the prototype of the probe microscope.

1974 The term “nanotechnology” was first proposed by the Japanese physicist N. Taniguchi in his report “On the Basic Concept of Nanotechnology” at an international conference long before the start of large-scale work in this area. The term was used to describe the ultra-fine processing of materials with nanometer precision. The term “nanotechnology” was proposed to refer to mechanisms smaller than one micrometer in size.

1981 German physicists G. Binning and G. Rohrer, employees of IBM (International Business Machines Corporation), created a scanning tunneling microscope (Nobel Prize 1986) - the first device that allows not only to obtain a three-dimensional image of a structure from an electrically conductive material with resolution order of size of individual atoms, but also to influence matter at the atomic level, i.e. manipulate atoms, and, therefore, directly assemble any substance from them.

1985 A team of scientists consisting of G. Croto (England), R. Curl, R. Smalley (USA) discovered a new allotropic form of the existence of carbon in nature - fullerene and studied its properties (Nobel Prize 1996). The possibility of the existence of spherical highly symmetrical carbon molecules was predicted in 1970 by Japanese scientists E. Osawa and Z. Yoshilda.

In 1973, Russian scientists D. A. Bochvar and E. G. Galpern used theoretical quantum chemical calculations to prove the stability of such molecules.

1986 A scanning atomic force microscope was created (authors: G. Binning, K. Kuatt, K. Gerber, IBM employees, Nobel Prize 1992), which, unlike the scanning tunneling microscope, made it possible to study the atomic structure of not only conductive, but also any materials, including organic molecules, biological objects, etc.

Nanotechnology has become known to the general public. The basic system concept, which comprehended previous achievements, was sounded in the book of the American futurologist, employee of the artificial intelligence laboratory of the Massachusetts Institute of Technology E. Drexler, “Engines of Creation: The Coming Era of Nanotechnology”. The author predicted the active development and practical application of nanotechnology. This forecast, calculated for many decades, is being justified step by step and significantly ahead of time.

1987 The first single-electron transistor was created by American physicists T. Futon and G. Dolan (Bell Labs).

French physicist J.M. Len introduced the concepts of “self-organization” and “self-assembly” into use, which became key concepts in the design of nano-objects.

1988-1989 Two independent groups of scientists led by A. Fehr and P. Grünberg discovered the phenomenon of giant magnetic resistance (GMR) - a quantum mechanical effect observed in thin films of alternating ferromagnetic and non-magnetic layers, manifested in a significant decrease in electrical resistance in the presence of an external magnetic field. Using this effect makes it possible to record data on hard drives with atomic information density (Nobel Prize 2007).

1989 The first practical achievement of nanotechnology was demonstrated: using a scanning tunneling microscope produced by IBM, American researchers D. Eigler,

E. Schweitzer laid out three letters of the company logo (“IBM”) from 35 xenon atoms by sequentially moving them on the surface of a nickel single crystal.

1990 A team of scientists led by W. Kretschmer (Germany) and

D. Huffman (USA) created an effective technology for the synthesis of fullerenes, which contributed to the intensive study of their properties and the identification of promising areas of their application.

1991 Japanese physicist S. Iijima discovered a new form of carbon

native clusters are carbon nanotubes, which exhibit a whole range of unique properties and are the basis for revolutionary transformations in materials science and electronics.

In Japan, a state program for the development of technology for manipulating atoms and molecules began to be implemented - the Atomic Technology project.

1993 The first nanotechnology laboratory was organized in the USA.

1994 A laser based on self-organized quantum dots was demonstrated for the first time (D. Bimberg, Germany).

1998 Dutch physicist S. Dekker created the first nanotransistor based on nanotubes.

Japan has launched the Astroboy program to develop nanoelectronics capable of operating in space.

1999 American scientists M. Reed and D. Tour developed unified principles for manipulating both one molecule and their chain.

The element base of microelectronics has crossed the 100 nm mark.

2000 The United States launched a large-scale nanotechnology research program called the National Nanotechnology Initiative (NNI).

German physicist R. Magerle proposed nanotomography technology - creating a three-dimensional picture of the internal structure of a substance with a resolution of 100 nm. The project was financed by Volkswagen.

2002 Hewlett Research Center staff

Packard (USA) F. Kukes and S. Williams patented a technology for creating microcircuits based on intersecting nanowires with complex logic implemented at the molecular level.

S. Dekker connected a carbon nanotube with DNA, obtaining a single nanomechanism.

2004 Graphene was created at the University of Manchester (Great Britain) - a material with a graphite structure one atom thick, a promising substitute for silicon in integrated circuits (scientists A. Geim and K. Novoselov were awarded the Nobel Prize in 2010 for the creation of graphene).

2005 Altar Nanotechnologies (USA) announced the creation of a nanobattery.

2006 Researchers from Northwestern University in the USA developed the first “printing press” for nanostructures - a facility that allows the production of more than 50 thousand nanostructures simultaneously in the nanoscale range with atomic precision and the same molecular template on the surface, which is the foundation for the future mass production of nanosystems.

American scientists from IBM succeeded for the first time in the world to create a fully functional integrated circuit based on a carbon nanotube.

D. Tour from Rice University (USA) created the first moving nanosystem - a molecular machine ~ 4 nm in size.

A group of scientists from the University of Portsmouth (UK) has developed the first DNA-based electronic bionanotechnology switch, which is a promising basis for communication between the “world” of living organisms and the “world” of computers.

Scientists from the California Institute of Technology (USA) have developed the first portable biosensor-blood analyzer (portable laboratory “lab-on-chip”).

2007 Intel (USA) began producing processors containing the smallest structural element measuring ~ 45 nm.

Employees of the Georgia Institute of Technology (Georgia, USA) have developed scanning lithography technology with a resolution of 12 nm.

The above and other studies, discoveries, and inventions gave a powerful impetus to the use of nanotechnological methods in industry. The rapid development of applied nanotechnology has begun.

The first commercial nanomaterials appeared - nanopowders, nanocoatings, bulk nanomaterials, nanochemical and nanobiological preparations; the first electronic devices and sensors for various purposes based on nanotechnology were created; Numerous methods for producing nanomaterials have been developed.

Many countries around the world have actively participated in research on nanotechnology issues at the level of governments and heads of state, assessing the prospects for the future. In leading universities and institutes of the world (USA, Germany, Japan, Russia, England, France, Italy, Switzerland, China, Israel, etc.) laboratories and departments of nanostructures have been created, headed by famous scientists.

Nanotechnologies are already used in the most significant areas of human activity - radio electronics, information technology, energy, transport, biotechnology, medicine, and the defense industry.

Today, more than 50 countries around the world are involved in nanoresearch.

Eight Nobel Prizes have been awarded for unique research results in this area.

2. Basic concepts of nanoscience

Nanoscience has emerged as an independent discipline only in the last 7-10 years. The study of nanostructures is a common direction for many classical scientific disciplines. Nanochemistry occupies one of the leading places among them, as it opens up almost unlimited possibilities for the development, production and research of new nanomaterials with specified properties, often superior in quality to natural materials.

Nanochemistry is a science that studies the properties of various nanostructures, as well as the development of new methods for their production, study and modification.

The priority task of nanochemistry is to establish a relationship between the size of a nanoparticle and its properties.

The objects of nanochemistry research are bodies with such a mass that their equivalent size remains within the nanointerval (0.1 - 100 nm).

Nanoscale objects occupy an intermediate position between bulk materials on the one hand, and atoms and molecules on the other. The presence of such objects in materials gives them new chemical and physical properties. Nanoobjects are an intermediate and connecting link between the world in which the laws of quantum mechanics operate and the world in which the laws of classical physics operate.

Figure 1. Characteristic sizes of objects in the surrounding world

Nanochemistry studies the preparation and properties of various nanosystems. Nanosystems are many bodies surrounded by a gas or liquid medium. Such bodies can be polyatomic clusters and molecules, nanodroplets and nanocrystals. These are intermediate forms between atoms and macroscopic bodies. The size of the systems remains in the range of 0.1 - 100 nm.

Table 1. Classification of nanochemical objects by phase state

nanoscience nanoparticle nanochemistry classification

The range of objects studied by nanochemistry is constantly expanding. Chemists have always sought to understand what is special about nanometer-sized bodies. This led to the rapid development of colloidal and macromolecular chemistry.

In the 80-90s of the 20th century, thanks to the methods of electron, atomic force and tunneling microscopy, it was possible to observe the behavior of nanocrystals of metals and inorganic salts, protein molecules, fullerenes and nanotubes, and in recent years such observations have become widespread.

Table 2. Objects of nanochemical research

Thus, the following main characteristics of nanochemistry can be distinguished:

1. The geometric dimensions of objects are on a nanometer scale;

2. Manifestation of new properties by objects and their collections;

3. Possibility of control and precise manipulation of objects;

4. Objects and devices assembled on the basis of objects receive new consumer properties.

3. Features of the structure and behavior of some nanoparticles

Nanoparticles made from inert gas atoms are the simplest nanoobjects. Atoms of inert gases with completely filled electron shells weakly interact with each other through van der Waals forces. When describing such particles, the hard ball model is used.

Metal nanoparticles. In metal clusters of several atoms, both covalent and metallic types of bonds can be realized. Metal nanoparticles are highly reactive and are often used as catalysts. Metal nanoparticles usually take regular shapes - octahedron, icosahedron, tetradecahedron.

Fractal clusters are objects with a branched structure: soot, colloids, various aerosols and aerogels. A fractal is an object in which, with increasing magnification, you can see how the same structure is repeated in it at all levels and on any scale.

Molecular clusters are clusters consisting of molecules. Most clusters are molecular. Their number and variety are enormous. In particular, many biological macromolecules belong to molecular clusters.

Fullerenes are hollow particles formed by polyhedra of carbon atoms connected by a covalent bond. A special place among fullerenes is occupied by a particle of 60 carbon atoms - C60, which resembles a microscopic soccer ball.

Nanotubes are hollow molecules consisting of approximately 1,000,000 carbon atoms and are single-layer tubes with a diameter of about a nanometer and a length of several tens of microns. On the surface of a nanotube, carbon atoms are located at the vertices of regular hexagons.

4. Types of applied uses of nanochemistry

Conventionally, nanochemistry can be divided into:

1. Theoretical

2. Experimental

3. Applied

Theoretical nanochemistry develops methods for calculating the behavior of nanobodies, taking into account such parameters of the state of particles as spatial coordinates and velocities, mass, characteristics of the composition, shape and structure of each nanoparticle.

Experimental nanochemistry is developing in three directions. Within the framework of the first, ultrasensitive spectral methods are developed and used, making it possible to judge the structure of molecules containing tens and hundreds of atoms. Within the framework of the second direction, phenomena under local (local) electrical, magnetic or mechanical influences on nanobodies, implemented using nanoprobes and special manipulators, are studied. Within the framework of the third direction, the macrokinetic characteristics of collectives of nanobodies and the distribution functions of nanobodies according to state parameters are determined.

Applied nanochemistry includes:

Development of theoretical foundations for the use of nanosystems in engineering and nanotechnology, methods for predicting the development of specific nanosystems under the conditions of their use, as well as the search for optimal methods of operation (technical nanochemistry).

Creation of theoretical models of the behavior of nanosystems during the synthesis of nanomaterials and search for optimal conditions for their production (synthetic nanochemistry).

Study of biological nanosystems and creation of methods for using nanosystems for medicinal purposes (medical nanochemistry).

Development of theoretical models for the formation and migration of nanoparticles in the environment and methods for purifying natural waters or air from nanoparticles (environmental nanochemistry).

5. Methods for obtaining nanoparticles

Preparation of nanoparticles in the gas phase:

1 Obtaining nanoparticles in the process of “evaporation - condensation”.

The following processes are most often carried out in the gas phase: evaporation - condensation (evaporation in an electric arc and in plasma); deposition; topochemical reactions (reduction, oxidation, decomposition of solid phase particles). In the evaporation-condensation process, liquid or solid substances are evaporated at a controlled temperature in a low-pressure inert gas atmosphere, followed by condensation of the vapor in a cooling medium or on cooling devices. This method makes it possible to obtain particles ranging in size from two to several hundred nanometers. Nanoparticles with a size of less than 20 nm are usually spherical in shape, while larger ones may appear faceted.

Typically, the substance to be evaporated is placed in a heating chamber with a heater and a hole (diaphragm), through which the evaporated particles of the substance enter a vacuum space (with a pressure of about 0.10 Pa), where a molecular beam is formed. The particles, moving almost linearly, condense on the cooled substrate. Gas is pumped out of the device through a valve. The source temperature is selected depending on the required intensity of the molecular beam and the equilibrium pressure above the evaporated material. It may be higher or lower than the melting point of the substance.

It should be noted that some substances (for example, Sn and Ge) evaporate both in the form of individual atoms and in the form of small clusters. In low-intensity molecular beams obtained by effusion through an opening in the heating chamber, a uniform distribution of small-sized clusters is observed. The main advantage of the molecular beam method is the ability to quite accurately regulate the beam intensity and control the rate of particle supply into the condensation zone.

2 Gas-phase production of nanoparticles.

The low-intensity molecular beam method is often combined with chemical deposition methods. Deposition is carried out near or directly on the cold surface of the apparatus under controlled temperature and reduced pressure to reduce the likelihood of particle collisions.

For the gas-phase production of nanoparticles, installations are used that differ in the methods of supplying and heating the evaporated material, the composition of the gaseous medium, the methods of carrying out the condensation process and the selection of the resulting powder. For example, the powder is deposited on a cooled rotating cylinder or drum and scraped off it into a receiving container.

The design diagram of an apparatus for gas-phase synthesis of metal nanopowders includes a working chamber, a cooled drum, a scraper, a funnel, a receiving container for powder, a heated tubular reactor, and a device for controlled supply of evaporated material and carrier gas. In a tubular reactor, the evaporated material is mixed with a carrier inert gas and transferred to the gas phase state.

The resulting continuous flow of clusters or nanoparticles flows from the reactor into the working chamber of the apparatus, in which a pressure of the order of 1 - 50 Pa is created. Condensation of nanoparticles and their deposition in the form of powder occurs on the surface of a cooled rotating drum. Using a scraper, the powder is removed from the surface of the drum; then it passes through a funnel into a receiving container and is sent for further processing.

Unlike evaporation in a vacuum, atoms of a substance evaporated in a rarefied atmosphere quickly lose kinetic energy due to collisions with gas atoms and form crystal nuclei (clusters). When they condense, nanocrystalline particles are formed. Thus, in the process of condensation of aluminum vapor in an environment of hydrogen, helium and argon at various gas pressures, particles with a size of 20 - 100 nm are obtained.

3 Preparation of nanoparticles using topochemical reactions.

Using topochemical reactions of certain gaseous media with metal nanoparticles at the moment of their condensation from the vapor phase, it is possible to obtain nanoparticles of the desired compounds. To obtain the required compound, the interaction of the evaporated metal with the reagent gas can be ensured directly in the gas phase.

In the method of gas-phase chemical reactions, the synthesis of nanomaterials occurs due to chemical transformations occurring in an atmosphere of vapors of highly volatile substances. Halides (especially metal chlorides), metal oxychlorides MeOnClm, alkoxides Me(OR)n, alkyl compounds Me(R)n, metal vapors, and so on are widely used as starting reagents. This method can produce nanomaterials of boron, carbon black, metals, alloys, nitrides, carbides, silicides, sulfides and other compounds.

When synthesizing nanomaterials using the method under consideration, the properties of the resulting products are largely influenced by the design of the reactors, the method of heating the reagents, the temperature gradient during the process, and a number of other factors.

Gas-phase chemical reactions are usually carried out in various types of tubular flow reactors. The most widespread are reactors with external heating of the reaction zone. Quartz compounds, ceramic materials or alumina are used as structural materials for the reaction zone of the apparatus.

Topochemical interaction of the gas phase with powder is used to apply various coatings to its particles and introduce modifying additives. In this case, it is necessary to regulate the degree of unevenness of the process so that the solid phase is released only on the surface of the particles, and not in the volume between the particles. For example, topochemical reactions include the interaction of oxides with nitrogen in the presence of carbon for the synthesis of nitrides. In this way, powders of silicon, aluminum, titanium and zirconium nitrides are synthesized.

The composition of the inert gas affects the rate of particle growth. Heavier atoms of the environment more intensively take energy from the condensed atoms and thereby contribute to the growth of particles, just as a decrease in the cooling temperature also contributes to the growth of particles. By changing the gas pressure in the apparatus and the composition of the gaseous medium, it is possible to obtain nanoparticles of various sizes. Thus, replacing helium with argon or xenon increases the size of the resulting nanoparticles several times.

The production of nanopowders in the gas phase is facilitated by the relatively low surface tension at the solid-gas interface; An increase in surface tension leads to compaction of nanoparticles in the aggregate. At the same time, high temperature accelerates diffusion processes, which promotes particle growth and the formation of solid bridges between particles. The main problem of the method under consideration is the separation of nanoparticles from the gas phase under conditions when the concentration of particles in the gas flow is low and the gas temperature is quite high. To capture nanoparticles, special filter devices are used (for example, metal-ceramic filters, electric precipitators), centrifugal sedimentation of solid particles in cyclones and hydrocyclones, and special gas centrifuges.

Nanoparticles can be formed as a result of the high temperature decomposition of solids containing metal cations, molecular anions or organometallic compounds. This process is called thermolysis. For example, small lithium particles can be obtained by decomposition of lithium azide LiIII. The substance is placed in an evacuated quartz tube and heated to 400 C in the installation. At a temperature of about 370 C, the azide decomposes with the release of gaseous N2, which can be determined by the increase in pressure in the evacuated space. After a few minutes, the pressure drops to the original level, indicating that all N2 has been removed. The remaining lithium atoms combine to form small colloidal metal particles. This method can produce particles with sizes less than 5 nm. Particles can be passivated by introducing an appropriate gas into the chamber.

Preparation of nanoparticles in the liquid phase:

1 Chemical condensation.

Chemical methods for producing nanoparticles and ultradisperse systems have been known for quite a long time. A colloidal solution of gold (red) sol with a particle size of 20 nm was obtained in 1857. M. Faraday. The aggregative stability of the sol is explained by the formation of a double electrical layer at the solid-solution interface and the appearance of an electrostatic component of disjoining pressure, which is the main factor in the stabilization of this system.

The simplest and most frequently used method is the synthesis of nanoparticles in solutions through various reactions. To obtain metal nanoparticles, reduction reactions are used, in which aluminum and borohydrides, tetraborates, hypophosphites and many other inorganic and organic compounds are used as reducing agents.

Nano-sized particles of metal salts and oxides are most often obtained in exchange and hydrolysis reactions. For example, a gold sol with a particle size of 7 nm can be obtained by reducing gold chloride with sodium borohydride using dodecanethiol as a stabilizer. Thiols are widely used to stabilize semiconductor nanoparticles. This method has extremely broad capabilities and allows one to obtain materials containing biologically active macromolecules.

2 Precipitation in solutions and melts.

Precipitation in solutions.

The general patterns of the formation of nanoparticles in liquid media depend on many factors: the composition and properties of the initial substance (solution, melt); the nature of the phase equilibrium diagram of the system under consideration; a method for creating supersaturation of a solution or melt; the equipment used and its operating modes.

In the case of synthesis of the necessary phases, the powder is heat treated after drying or these phases are combined into one. After heat treatment, the aggregates are disaggregated to nanoparticle sizes.

The starting materials and solvent are chosen so that by-products can be completely removed from the target product during washing and subsequent heat treatment without polluting the environment. To effectively mix reagents, mixing devices with various types of mixers (propeller, rod, turbine), circulation mixing using pumps (centrifugal and gear), dispersing devices (nozzles, nozzles, injectors, rotating disks, acoustic sprayers, etc.) are used.

On the one hand, to increase reactor productivity, the solubility of the starting substances must be high. However, when obtaining nanoparticles, this will increase their mass content in the resulting suspension and the likelihood of combining into aggregates.

On the other hand, to ensure a high degree of nonequilibrium in the process of formation of the solid phase, it is necessary to use saturated solutions of the starting substances. In order to maintain a small proportion of nanoparticles in the suspension, it is advisable to use slightly soluble starting substances. In this case, the reactor productivity will decrease. Another possibility is to use a small amount of precipitant and a large excess of precipitant. When deposition in aqueous solutions, solutions of ammonia, ammonium carbonate, oxalic acid or ammonium oxolate are most often used as precipitants. Well-soluble salts of nitric, hydrochloric or acetic acids are chosen as starting materials for precipitation.

By regulating the pH and temperature of the solution, it is possible to create conditions for the production of highly dispersed hydroxides. The product is then calcined and, if necessary, reduced. The resulting metal powders have a size of 50 - 150 nm and a spherical or close to spherical shape. The deposition method can be used to obtain metal oxide and metal oxide materials, compositions based on them, various ferrites and salts.

The critical stage that determines the properties of the resulting powder is its separation from the liquid phase. With the emergence of a gas-liquid interface, the Laplace forces and compressible particles increase sharply. As a result of the action of these forces, compressive pressures of the order of megapascals arise in nanosized particles, which are used when compacting macroparticles into monolithic porous products. In this case, hydrothermal conditions are created in the pores of the aggregate, leading to an increase in the solubility of particles and the strengthening of aggregates due to the dissolution-condensation mechanism. The particles combine into a strong aggregate, and then into a separate crystal.

To remove the liquid phase from the sediment, the processes of filtration, centrifugation, electrophoresis, and drying are used. The likelihood of the formation of durable aggregates can be reduced by replacing water with organic solvents, as well as using surfactants, freeze drying, and using a drying agent under supercritical conditions.

A variation of the technology for producing nanoparticles in liquid media is the controlled dissolution of larger particles in suitable solvents. To do this, it is necessary to slow down or even stop the process of their dissolution in the nanosize range. Using the same method, it is possible to correct the sizes of particles obtained by the listed methods in cases where their size turns out to be larger than necessary.

Precipitation in melts.

With this method, the liquid medium is molten salts or metals (molten salts are most often used). The formation of the solid phase occurs at a sufficiently high temperature, when diffusion processes cause a high rate of crystal growth. The main problem in this case is to avoid the capture of side compounds by the synthesized powder. To isolate the synthesized powder after cooling, the salt is dissolved in suitable solvents.

By changing the degree of nonequilibrium of the process, the structure of the material can be adjusted. If the process is stopped at the stage when the solid phase is nanosized, a nanomaterial can be obtained. However, this is very difficult to do due to the high rate of diffusion mass transfer at a fairly high temperature of the environment.

This method is more promising for obtaining nanoparticles by dissolving the original larger particles. In this case, it is possible to immediately obtain a nanocomposite if a dissolving medium, for example a glassy one, plays the role of a matrix for nanoparticles.

3 Sol-gel method.

The sol-gel method includes several main technological phases. Initially, aqueous or organic solutions of the starting substances are obtained. Sols (colloidal systems) with a solid dispersed phase and a liquid dispersion medium are formed from solutions to obtain a sol, for example, the hydrolysis of salts of weak bases or alcoholates is used. You can also use other reactions leading to the formation of stable and concentrated sols (for example, the use of peptizers - substances that prevent the decomposition of particle aggregates in disperse systems). It is effective to apply a protective layer of water-soluble polymers or surfactants to nanoparticles during the hydrolysis process, added along with water during the hydrolysis process.

Subsequently, the sol is converted into a gel by removing part of the water from it by heating and extraction with an appropriate solvent. In some cases, an aqueous sol is sprayed into a heated organic liquid that is immiscible with water.

By converting the sol into a gel, structured colloidal systems are obtained. Solid particles of the dispersed phase are interconnected into a loose spatial network, which contains a liquid dispersion medium in its cells, depriving the system as a whole of fluidity. Contacts between particles are easily and reversibly destroyed by mechanical and thermal influences. Gels with an aqueous dispersion medium are called hydrogels, and those with a hydrocarbon dispersion medium are called organogels.

By drying the gel, one can obtain aerogels or xerogels - fragile microporous bodies (powders). Powders are used for molding products, plasma spraying, and so on. The gel can be used directly to produce films or monolithic products. Currently, the sol-gel method is widely used to obtain nanoparticles from inorganic non-metallic materials.

4 Electrochemical method for producing nanoparticles.

The electrochemical method is associated with the release of a substance at the cathode during electrolysis of simple and complex cations and anions. If a system consisting of two electrodes and an electrolyte solution (melt) is included in a direct electric current circuit, then oxidation-reduction reactions will occur at the electrodes. At the anode (positive electrode), the anions give up electrons and become oxidized; At the cathode (negative electrode), cations gain electrons and are reduced. The deposit formed on the cathode as a result, for example, of electrocrystallization, morphologically can be either a loose or a dense layer of many microcrystallites.

The texture of the sediment is influenced by many factors, such as the nature of the substance and solvent, the type and concentration of ions of the target product and foreign impurities, the adhesive properties of the deposited particles, the temperature of the medium, the electrical potential, diffusion conditions, and others. One of the promising scientific directions is the use of electrochemical synthesis for the design of nanostructured materials. Its essence lies in the formation of two-dimensional (Langmuir) monolayers of metal nanoparticles under monolayer surfactant matrices during kinetically controlled electroreduction. The main advantages of the method are experimental accessibility and the ability to control and manage the process of obtaining nanoparticles.

Preparation of nanoparticles using plasma:

1 Plasmochemical synthesis.

One of the most common chemical methods for producing ultrafine powders of metals, nitrides, carbides, oxides, borides, as well as their mixtures, is plasma-chemical synthesis. This method is characterized by a very fast (in 10.3 - 10.6 s) reaction occurring far from equilibrium and a high rate of formation of a new phase at a relatively low rate of their growth.

In plasma-chemical synthesis, low-temperature (400 - 800 K) nitrogen, ammonia, hydrocarbon, and argon plasma is used, which is created using an electric arc, an electromagnetic high-frequency field, or a combination of both in reactors called plasmatrons. In them, a stream of starting substances (gaseous, liquid or solid) quickly flies through the zone where the plasma is maintained, receiving energy from it to carry out chemical transformation reactions. The plasma-forming gas can also be the original substance itself.

The reactor includes the following main components: electrodes, pipes for the input of plasma-forming gas, coils of electromagnets to maintain the plasma arc, pipes for introducing reagents, cold gas input devices, and a receiving device for synthesis products. The arc column formed between the electrodes forms a plasma flow, and a temperature of 1200 - 4500 K is reached in the reactor. The resulting products are hardened in various ways: in tubular heat exchangers, by flooding the flow of the reacting mixture with jets of cold gases or liquid, in cooled Laval nozzles.

The characteristics of the resulting powders depend on the raw materials used, synthesis technology and type of plasmatron; their particles are single crystals and have sizes of 10 - 100 nm or more. The processes occurring during plasma-chemical synthesis and the gas-phase method for producing nanoparticles are close to each other. After interaction in the plasma, active particles are formed in the gas phase. In the future, it is necessary to preserve their nanosizes and separate them from the gas phase.

Plasma-chemical synthesis powders are characterized by a wide distribution of nanoparticles in size and, as a consequence, the presence of fairly large (up to 1 - 5 μm) particles, that is, low selectivity of the process, as well as a high content of impurities in the powder.

To obtain nanoparticles, you can use not only the method of their growth, but also the dissolution of larger particles in plasma. In practice, reactors are used in which laser radiation is introduced into the working volume through a special window and a flow of the reaction mixture. In the area of ​​their intersection, a reaction zone appears where the formation of particles occurs. The particle size depends on the reactor pressure and laser radiation intensity. The parameters of laser radiation are much easier to control (than high-frequency or arc plasma), which makes it possible to obtain a narrower particle size distribution. In this way, silicon nitride powder with particle sizes of 10 - 20 nm was obtained.

2 Electroerosive method.

The essence of the method is the formation of an arc between electrodes immersed in a bath of liquid. Under these conditions, the substance of the electrodes is partially dispersed and interacts with the liquid to form a dispersed powder. For example, electrical erosion of aluminum electrodes in water leads to the formation of aluminum hydroxide powder.

The resulting solid precipitate is separated from the liquid phase by filtration, centrifugation, and electrophoresis. The powder is then dried and, if necessary, pre-crushed. In the process of subsequent heat treatment, the target product is synthesized from the powder, from which particles of the required size are obtained during the disaggregation process. This method can produce nano-sized particles if large-sized particles are placed in the liquid phase.

3 Shock wave or detonation synthesis.

Using this method, nanoparticles are produced in plasma formed during the explosion of high explosives (HE) in an explosion chamber (detonation tube).

Depending on the power and type of explosive device, shock-wave interaction on the material occurs in a very short period of time (tenths of microseconds) at a temperature of more than 3000 K and a pressure of several tens of hectopascals. Under such conditions, a phase transition in substances is possible with the formation of ordered dissipative nano-sized structures. The shock wave method is most effective for materials whose synthesis is carried out at high pressures, for example, diamond powders, cubic boron nitrate and others.

During the explosive transformation of condensed explosives with a negative oxygen balance (a mixture of TNT and hexogen), carbon is present in the reaction products, from which a diamond dispersed phase with a particle size of the order of 4 - 5 nm is formed.

By exposing porous structures of various metals and their salts, gels of metal hydroxides to shock waves from an explosive charge, it is possible to obtain nanopowders of Al, Mg, Ti, Zn, Si and others oxides.

The advantage of the shock wave synthesis method is the possibility of obtaining nanopowders of various compounds not only of ordinary phases, but also of high-pressure phases. At the same time, the practical application of the method requires special premises and technological equipment for carrying out blasting operations.

Mechanochemical synthesis.

This method provides mechanical processing of solids, which results in grinding and plastic deformation of the substances. The grinding of materials is accompanied by the breaking of chemical bonds, which predetermines the possibility of the subsequent formation of new chemical bonds, that is, the occurrence of mechanochemical reactions.

The mechanical impact when grinding materials is pulsed; in this case, the emergence of a stress field and its subsequent relaxation do not occur during the entire time the particles are in the reactor, but only at the moment of particle collision and in a short time after it. Mechanical action is not only impulsive, but also local, since it does not occur throughout the entire mass of the solid, but only where a stress field arises and then relaxes.

The impact of energy released at a high degree of nonequilibrium during impact or abrasion, due to the low thermal conductivity of solids, leads to the fact that some part of the substance is in the form of ions and electrons - in the state of plasma. Mechanochemical processes in a solid can be explained using the phonon theory of destruction of brittle bodies (a phonon is a quantum of energy of elastic vibrations of a crystal lattice).

Mechanical grinding of solid materials is carried out in ultrafine grinding mills (ball, planetary, vibration, jet). When the working bodies interact with the material being ground, it can be locally heated for a short time to high (plasma) temperatures, which are obtained under normal conditions at high temperatures.

Nanopowders with particle sizes from 200 to 5 - 10 nm can be obtained mechanically. So, when grinding a mixture of metal and carbon for

After 48 hours, particles of TiC, ZrC, VC and NbC with a size of 7 - 10 nm were obtained. In a ball mill, WC-Co nanocomposite particles with a particle size of 11-12 nm were obtained from a mixture of tungsten carbon and cobalt powders with an initial particle size of about 75 microns in 100 hours.

Biochemical methods for obtaining nanomaterials.

Nanomaterials can also be produced in biological systems. In many cases, living organisms, such as some bacteria and protozoa, produce minerals with particles and microscopic structures in the nanometer size range.

Biomineralization processes operate through mechanisms of fine biochemical control, resulting in the production of materials with well-defined characteristics.

Living organisms can be used as a direct source of ultrafine materials, the properties of which can be changed by varying the biological conditions of synthesis or processing. Ultrafine materials obtained by biochemical synthesis methods can be starting materials for some already tested and known methods of synthesis and processing of nanomaterials, as well as in a number of technological processes. So far there is little work in this area of ​​research, but it is already possible to point out a number of examples of the production and use of biological nanomaterials.

Currently, ultradisperse materials can be obtained from a number of biological objects, for example, ferritins and related proteins containing iron, magnetic bacteria, and others. Thus, ferritins (a type of protein) provide living organisms with the ability to synthesize nanometer-sized particles of iron hydroxides and oxyphosphates. The ability of magnetotactic bacteria to use the Earth's magnetic field lines for their own orientation allows them to have chains of nanosized (40 - 100 nm) single-domain magnetite particles.

It is also possible to obtain nanomaterials using microorganisms. Currently, bacteria have been discovered that oxidize sulfur, iron, hydrogen and other substances. With the help of microorganisms, it has become possible to carry out chemical reactions to extract various metals from ores, bypassing traditional technological processes. Examples include the technology of bacterial leaching of copper from sulfide materials, uranium from ores, and separation of arsenic impurities from tin and gold concentrates.

In some countries, up to 5% of copper and large amounts of uranium and zinc are currently obtained by microbiological methods. There are good prerequisites, confirmed by laboratory studies, for the use of microbiological processes for the extraction of manganese, bismuth, lead, and germanium from low-grade carbonate ores. With the help of microorganisms, it is possible to reveal the finely disseminated gold of arsenopyrite concentrates. Therefore, a new direction has appeared in technical microbiology, which is called microbiological hydrometallurgy.

Cryochemical synthesis.

The high activity of metal atoms and clusters in the absence of stabilizers causes the reaction into larger particles. The process of aggregation of metal atoms occurs practically without activation energy. Stabilization of active atoms of almost all elements of the periodic table was achieved at low (77 K) and ultra-low (4 - 10 K) temperatures using the matrix isolation method. The essence of this method is the use of inert gases at ultra-low temperatures. Argon and xenon are most often used as a matrix. Pairs of metal atoms condense with a large, usually thousandfold, excess of inert gas onto a surface cooled to 10 - 12 K. Significant dilution of inert gases and low temperatures practically eliminate the possibility of diffusion of metal atoms, and they are stabilized in the condensate. The physicochemical properties of such atoms are studied by various spectral and radiospectral methods.

Basic processes of cryochemical nanotechnology:

1 Preparation and dispersion of solutions.

As a result of dissolving the initial substance or substances in a particular solvent, it is possible to achieve the maximum possible degree of mixing of the components in a homogeneous solution, in which a high degree of accuracy of compliance with the given composition is guaranteed. Water is most often used as a solvent; however, it is possible to use other solvents that are easily frozen and sublimated.

The resulting solution is then dispersed into individual droplets of the required size, and they are cooled until the moisture is completely frozen. The process of hydrodynamic dispersion is carried out due to the flow of solution through various nozzles and filters, as well as using nozzles.

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Nanochemistry

Chemistry and pharmacology

Nanoscience has emerged as an independent discipline only in the last 7-10 years. The study of nanostructures is a common direction for many classical scientific disciplines. Nanochemistry occupies one of the leading places among them, as it opens up almost unlimited possibilities for the development, production and research...

FEDERAL AGENCY FOR EDUCATION OMSK STATE PEDAGOGICAL UNIVERSITY FACULTY OF CHEMISTRY AND BIOLOGY
DEPARTMENT OF CHEMISTRY AND METHODS OF TEACHING CHEMISTRY

Nanochemistry

Completed by: student 1-ХО Kuklina N.E.

Checked by: Ph.D., Associate Professor B.Ya. Bryansky.

Omsk 2008

§1. History of the formation of nanoscience………………………………………………………3

§2. Basic concepts of nanoscience…………………………………………………………….5

§3. Features of the structure and behavior of some nanoparticles……………………………8

§4. Types of applied uses of nanochemistry……………………………………………………….....9

§5. Methods for obtaining nanoparticles………………………………………………………..10

§6. Nanomaterials and prospects for their application……………………………………...11

Sources of information…………………………………………………………………………………13

§1. History of the formation of nanoscience

1905 Albert Einstein theoretically proved that the size of a sugar molecule is p and veins are 1 nanometer.

1931 German physicists Ernst Ruska and Max Knoll created the electron microscope O scope providing 10 15 -fold increase.

1932 Dutch professor Fritz Zernike invented phase-contrast mi To roscope a variant of an optical microscope that improved the quality of displaying image details A zheniya, and studied living cells with its help.

1939 Siemens, where Ernst Ruska worked, produced the first commercial electron microscope with a resolution of 10 nm.

1966 American physicist Russell Young, who worked at the National Bureau of Hundred n darts, invented the engine used today in scanning tunnel micros O scopes and for positioning nanoinstruments with an accuracy of 0.01 angstroms (1 nanometer = 10 angstroms).

1968 Bell Executive Vice President Alfred Cho and John Arthur, an employee of its semiconductor research department, substantiated the theoretical possibility of using nanotechnology in solving problems of surface treatment and achieving atomic precision in the creation of electronic devices.

1974 Japanese physicist Norio Taniguchi, who worked at the University of Tokyo, proposed the term "nanotechnology" (the process of dividing, assembling and changing matter A fishing by exposing them to one atom or one molecule), which quickly gained popularity in scientific circles.

1982 At the IBM Zurich Research Center, physicists Gerd Binnig and Ge n Rich Rohrer created a scanning tunneling microscope (STM), which allows one to construct a three-dimensional picture of the arrangement of atoms on the surfaces of conducting materials.

1985 Three American chemists: Rice University professor Richard Smalley, as well as Robert Karl and Harold Kroto, discovered fullerenes - molecules composed I consisting of 60 carbon atoms arranged in the shape of a sphere. These scientists were also able to measure an object 1 nm in size for the first time.

1986 Gerd Binnig developed a scanning atomic force probe micro O scope, which finally made it possible to visualize atoms of any materials (not only O drivers), as well as manipulate them.

19871988 At the Delta Research Institute under the leadership of P.N. Luskinovich put into operation the first Russian nanotechnological installation, which carried out the directed escape of particles from the tip of a microscope probe under the influence of heating.

1989 Scientists Donald Eigler and Erhard Schwetzer from the California IBM Research Center managed to lay out the name of their company with 35 xenon atoms on a nickel crystal.

1991 Japanese professor Sumio Lijima, who worked at NEC, and With used fullerenes to create carbon tubes (or nanotubes) with a diameter of 0.8 nm.

1991 The first nanotechnology program of the National Science Foundation was launched in the United States. The Japanese government is also engaged in similar activities.

1998 Cees Dekker, a Dutch professor at the Delfts Technical University, created a transistor based on nanotubes. To do this, he had to be the first in the world to change e determine the electrical conductivity of such a molecule.

2000 German physicist Franz Gissibl saw subatomic particles in silicon. His colleague Robert Magerle proposed nanotomography technology to create three-dimensional R a new picture of the internal structure of matter with a resolution of 100 nm.

2000 The US government opened the National Nanotechnology Institute And initiative (NNI). The US budget allocated $270 million for this area, commercial e Chinese companies invested 10 times more in it.

2002 Cees Dekker connected a carbon tube with DNA, creating a single nano e mechanism.

2003 Professor Feng Liu from the University of Utah, using the work of Franz Gissibl, used an atomic microscope to construct images of electron orbits by analyzing their perturbation as they move around the nucleus.

§2. Basic concepts of nanoscience

Nanoscience emerged as an independent discipline only after d age 7-10 years. The study of nanostructures is a common direction for many classical scientific disciplines. Nanochemistry occupies one of the leading places among them, as it opens up almost unlimited possibilities for the development, production and research of new nanomaterials with specified properties, often superior in quality to natural materials.

Nanochemistry - is a science that studies the properties of various sediments T structures, as well as the development of new methods for their production, study and modification.

The priority task of nanochemistry isestablishing a relationship between the size of nanoparticles A stitsa and its properties.

Objects of nanochemistry researchare bodies with such a mass that their equivalent And the valence size remains within the nanorange (0.1 100 nm).

Nanoscale objects occupy an intermediate position between bulk materials on the one hand, and atoms and molecules on the other. The presence of suchъ ects in materials gives them new chemical and physical properties. Nanoobjects are an intermediate and connecting link between the world in which they operate. O knowledge of quantum mechanics, and the world in which the laws of classical physics operate.

Characteristic sizes of objects in the surrounding world

Nanochemistry studies the preparation and properties of various nanosystems. Nanosystems represent a set of bodies surrounded by a gas or liquid medium. Such t e They can be polyatomic clusters and molecules, nanodroplets and nanocrystals. These are intermediate forms between atoms and macroscopic bodies. Systems size about With lies within 0.1 100 nm.

Classification of nanochemical objects by phase state

The range of objects studied by nanochemistry is constantly expanding. Chemists have always sought to understand what is special about nanometer-sized bodies. This led to the rapid development of colloidal and macromolecular chemistry.

In the 80-90s of the XX century, thanks to the methods of electronic, atomic force and n nel microscopy, it was possible to observe the behavior of nanocrystals of metals and n e organic salts, protein molecules, fullerenes and nanotubes, and in recent years t A These observations became widespread.

Objects of nanochemical research

Thus, the following main characteristics of nanochemistry can be distinguished:

1. The geometric dimensions of objects are on a nanometer scale;
2. Manifestation of new properties by objects and their collections;
3. Ability to control and precisely manipulate objects;
4. Objects and devices assembled on the basis of objects receive new consumers bskie properties.

§3. Features of the structure and behavior of some nanoparticles

Nanoparticles from noble gas atomsare the simplest nanoobjectsъ ects. Atoms of inert gases with completely filled electron shells weakly interact with each other through van der Waals forces. When describing such particles, the model of hard spheres is used.

Metal nanoparticles. In metal clusters of several atoms, both covalent and metallic types of bonds can be realized. Metal nanoparticles are highly reactive and are often used as catalysts. A torov. Metal nanoparticles usually take the regular shape of an octahedron, icos A hedron, tetradecahedron.

Fractal clustersthese are objects with a branched structure: soot, co l loids, various aerosols and aerogels. Fractal is an object in which, with age, With With increasing magnification, one can see how the same structure is repeated in it at all levels and on any scale.

Molecular clustersclusters consisting of molecules. Most clasts e ditch are molecular. Their number and variety are enormous. In particular, to molecules at Many biological macromolecules belong to polar clusters.

Fullerenes are hollow inside particles formed by polygons n nicks made of carbon atoms linked by a covalent bond. A special place among fuller e newly occupied by a particle of 60 carbon atoms C 60 , resembling a microscopic soccer ball.

Nanotubes these are hollow molecules inside, consisting of approximately 1,000,000 at O carbon and are single-layer tubes with a diameter of about a nanometer and a length of several tens of microns. On the surface of the nanotube, carbon atoms are dissolved O laid at the vertices of regular hexagons.

§4. Types of applied uses of nanochemistry

Conventionally, nanochemistry can be divided into:

• Theoretical
• Experimental
• Applied

Theoretical nanochemistrydevelops methods for calculating the behavior of nanobodies, taking into account such parameters of the state of particles as spatial coordinates and speed O size, mass, characteristics of the composition, shape and structure of each nanoparticle.

Experimental nanochemistrydevelops in three directions. As part of the first ultrasensitive spectral methods are being developed and used, yes Yu making it possible to judge the structure of molecules containing tens and hundreds of atoms.Within the seconddirections, phenomena under local (local) electrical e scientific, magnetic or mechanical effects on nanobodies, implemented using nanoprobes and special manipulators.As part of the thirdI determine directions T Xia macrokinetic characteristics of nanobody collectives and n distribution functions A notel according to state parameters.

Applied nanochemistry includes:

• Development of theoretical foundations for the use of nanosystems in engineering and nanotechnology O ology, methods for predicting the development of specific nanosystems under their conditions and With use, as well as searching for optimal methods of operation (technical and nochemistry).
• Creation of theoretical models of the behavior of nanosystems during the synthesis of nanomats e rials and the search for optimal conditions for their production (synthetic nanochemistry).
• Study of biological nanosystems and creation of methods for using nanometers And stems for medicinal purposes (medical nanochemistry).
• Development of theoretical models of the formation and migration of nanoparticles in the environment at harsh environment and methods for purifying natural waters or air from nanoparticles (ec O logical nanochemistry).

§5. Methods for obtaining nanoparticles

Fundamentally, all methods for the synthesis of nanoparticles can be divided into two large groups:

Dispersion methods, or methods for obtaining nanoparticles by grinding a conventional macrosample

condensation methods, or methods of “growing” nanoparticles from individual atoms.

Dispersion methods

With dispersion methods, the starting bodies are crushed into nanoparticles. This approach to obtaining nanoparticles is figuratively called by some scientists“top to bottom approach” . This is the simplest of all ways to create nanoparticles, a kind of “meat” O cutting” for macrobodies. This method is widely used in the production of materials for microelectronics; it consists in reducing the size of objects to nanoscale sizes within the capabilities of industrial equipment and the material used. AND h It is possible to grind a substance into nanoparticles not only mechanically. The Russian company Advanced Powder Technologies produces nanoparticles by exploding a metal thread with a powerful current pulse.

There are also more exotic ways to obtain nanoparticles. American scientists collected microorganisms from fig tree leaves in 2003 Rhodococcus and placed them in a gold-containing solution. The bacteria acted as a chemical With stabilizing agent, collecting neat nanoparticles with a diameter of about 10 nm from silver ions. By building nanoparticles, the bacteria felt normal and continued to multiply.

Condensation methods

With condensation methods (“bottom-up approach”) nanoparticles receive n at themes of unification of individual atoms. The method is that in controlled With In these conditions, ensembles of atoms and ions are formed. As a result, new objects are formed with new structures and, accordingly, with new properties, which can be programmed by changing the conditions for the formation of ensembles. This one d The move makes it easier to solve the problem of miniaturization of objects, brings us closer to solving a number of problems in high-resolution lithography, the creation of new microprocessors, thin polymer films, and new semiconductors.

§6. Nanomaterials and prospects for their application

The concept of nanomaterials was first formulated in80s of the XX century by G. Gleiter, who introduced the term itself into scientific use “ nanomaterial " In addition to traditional nanomaterials (such as chemical elements and compounds, amorphous substances, metals and their alloys), these include nanosemiconductors, nanopolymers, n A nonporous materials, nanopowders, numerous carbon nanostructures, n A nobiomaterials, supramolecular structures and catalysts.

Factors that determine the unique properties of nanomaterials, are the dimensional, electronic and quantum effects of the nanoparticles that form them, as well as their very developed surface. Numerous studies have shown that b significant and technically interesting changes in the physical and mechanical properties of nanomaterials (strength, hardness, etc.) occur in the particle size range from several n A numbers up to 100 nm. At present, many nanomaterials based on nitrides and borides with a crystallite size of about 12 nm or less have already been obtained.

Due to the specific properties of the nanoparticles underlying them, such mats e Rials are often superior to “regular” ones in many respects. For example, meta strength l la obtained by means of nanotechnology exceeds the strength of conventional material by 1.53 times, its hardness is 5070 times greater, and its corrosion resistance is 1012 times greater.

Application areas of nanomaterials:

• elements of nanoelectronics and nanophotonics (semiconductor transistors and lasers; photodetectors; solar cells; various sensors)
• ultra-dense information recording devices
• telecommunications, information and computing technologies, supe r computers
• video equipment flat screens, monitors, video projectors
• molecular electronic devices, including switches and electronic circuits at the molecular level
• fuel cells and energy storage devices
• devices of micro- and nanomechanics, including molecular motors and nanomotors, nanorobots
• nanochemistry and catalysis, including combustion control, coating, electrical To trochemistry and pharmaceuticals
• aviation, space and defense applications condition monitoring devices I environmental research
• targeted delivery of drugs and proteins, biopolymers and healing of biological tissues, clinical and medical diagnostics, creation of artificial muscles at fishing, bones, implantation of living organs
• biomechanics, genomics, bioinformatics, bioinstrumentation
• registration and identification of carcinogenic tissues, pathogens and biologically harmful agents; safety in agriculture and food production.

Omsk region is ready to develop nanotechnology

The development of nanotechnology is one of the priority areas for the development of science, technology and engineering in the Omsk region.

Thus, in the Omsk branch of the Institute of Semiconductor Physics SB RAS, research is being carried out h work on nanoelectronics, and at the Institute of Hydrocarbon Processing Problems of the SB RAS, work is underway to obtain nanoporous carbon supports and catalysts.

Information sources:

• http://www.rambler.ru/cgi-bin/news
• http://www.rambler.ru/news
• ht tp : // Nanometer.ru
• http://www.nanonewsnet.ru/ 67 KB Lesson equipment: Presentation The beginning of the Great Patriotic War, which uses a map of the initial period of the war, fragments of documentaries about the war, a diagram about the readiness of Germany and the USSR for war, an exhibition of books dedicated to the Great Patriotic War...

Distance educational courses are a modern form of effective additional education and advanced training in the field of training specialists for the development of promising technologies for the production of functional materials and nanomaterials. This is one of the promising forms of modern education developing throughout the world. This form of acquiring knowledge is especially relevant in such an interdisciplinary field as nanomaterials and nanotechnology. The advantages of distance courses are their accessibility, flexibility in constructing educational routes, improved efficiency and efficiency of the process of interaction with students, cost-effectiveness compared to full-time courses, which, however, can be harmoniously combined with distance learning. In the field of fundamental principles of nanochemistry and nanomaterials, video materials have been prepared by the Moscow State University Scientific and Educational Center for Nanotechnologies:

• . Basic concepts and definitions of nanosystem sciences and nanotechnologies. History of the emergence of nanotechnology and nanosystem sciences. Interdisciplinarity and multidisciplinarity. Examples of nanoobjects and nanosystems, their features and technological applications. Objects and methods of nanotechnology. Principles and prospects for the development of nanotechnology.
• . Basic principles of nanosystem formation. Physical and chemical methods. Processes for obtaining nanoobjects “from top to bottom”. Classical, “soft”, microsphere, ion beam (FIB), AFM - lithography and nanoindentation. Mechanical activation and mechanosynthesis of nanoobjects. Processes for obtaining nanoobjects “bottom-up”. Nucleation processes in gaseous and condensed media. Heterogeneous nucleation, epitaxy and heteroepitaxy. Spinodal decay. Synthesis of nanoobjects in amorphous (glassy) matrices. Chemical homogenization methods (co-precipitation, sol-gel method, cryochemical technology, aerosol pyrolysis, solvothermal treatment, supercritical drying). Classification of nanoparticles and nanoobjects. Techniques for obtaining and stabilizing nanoparticles. Aggregation and disaggregation of nanoparticles. Synthesis of nanomaterials in one and two-dimensional nanoreactors.
• . Statistical physics of nanosystems. Features of phase transitions in small systems. Types of intra- and intermolecular interactions. Hydrophobicity and hydrophilicity. Self-assembly and self-organization. Micelle formation. Self-assembled monolayers. Langmuir-Blodgett films. Supramolecular organization of molecules. Molecular recognition. Polymer macromolecules, methods for their preparation. Self-organization in polymer systems. Microphase separation of block copolymers. Dendrimers, polymer brushes. Layer-by-layer self-assembly of polyelectrolytes. Supramolecular polymers.
• . Substance, phase, material. Hierarchical structure of materials. Nanomaterials and their classification. Inorganic and organic functional nanomaterials. Hybrid (organic-inorganic and inorganic-organic) materials. Biomineralization and bioceramics. Nanostructured 1D, 2D and 3D materials. Mesoporous materials. Molecular sieves. Nanocomposites and their synergistic properties. Structural nanomaterials.
• . Catalysis and nanotechnology. Basic principles and concepts in heterogeneous catalysis. Influence of preparation and activation conditions on the formation of the active surface of heterogeneous catalysts. Structure-sensitive and structure-insensitive reactions. Specificity of thermodynamic and kinetic properties of nanoparticles. Electrocatalysis. Catalysis on zeolites and molecular sieves. Membrane catalysis.
• . Polymers for structural materials and functional systems. "Smart" polymer systems capable of performing complex functions. Examples of “smart” systems (polymer fluids for oil production, smart windows, nanostructured membranes for fuel cells). Biopolymers as the most “smart” systems. Biomimetic approach. Sequence design to optimize the properties of smart polymers. Problems of molecular evolution of sequences in biopolymers.
• . The current state and problems of creating new materials for chemical power sources: solid oxide fuel cells (SOFC) and lithium batteries are considered. Key structural factors are analyzed that influence the properties of various inorganic compounds, which determine the possibility of their use as electrode materials: complex perovskites in SOFCs and transition metal compounds (complex oxides and phosphates) in lithium batteries. The main anode and cathode materials used in lithium batteries and recognized as promising are considered: their advantages and limitations, as well as the possibility of overcoming limitations by directed changes in the atomic structure and microstructure of composite materials through nanostructuring in order to improve the characteristics of current sources.

Selected issues are discussed in the following book chapters (Binom Publishing):

Illustrative materials on nanochemistry, self-assembly and nanostructured surfaces:

Scientifically popular "video books":

Selected chapters of nanochemistry and functional nanomaterials.