Bactericidal paints. Bactericidal properties of silver nano particles.Why nano?Within the last years the nano technology began to be considered not only as one of the most challenging branches of high technology, but also as the backbone factor of economy of the 21st century– the economy based on knowledge, instead of on use of natural resources or their processing. Besides the nanotechnology stimulates development of a new paradigm of all industrial activity it is a source of new approaches to improvement of quality of a life and the solution of many social problems in a postindustrial society. According to the majority of experts in the field of a scientific and technical policy and investment of the means, the broken out nanotechnology revolution will reach all vital fields of activity of the humanity (from an outer space exploration — to medicine, from national defense — to ecology and agriculture), and its effect will be more extensive and deeper, than computer revolution of last third of the 20th century. One of the most developing areas of modern nanotechnology – is creation and usage of nano sized particles of various materials.
The nano material, which already has an application in various commercial products – is NANO SILVER.
Typical silver nano particles have sizes of 50-200 nanometers. It have big enough specific surface area that increases contact area of silver with bacteria or viruses, essentially improving its bactericidal actions. Thus, silver application as in a nano size allows to lower in hundreds times concentration of silver with preservation of all bactericidal properties.
Why silver? It is well-known that silver is the strongest natural antibiotic from existing on the earth. It is proved that silver is capable to destroy more than 650 kinds of bacteria, that is why it was used by people for destruction of various microorganisms through millennia that indicates to its stable antibiotic effect. A wide spectrum of silver antimicrobic actions, absence of tolerance to it of the majority of pathogenic microorganisms, low toxicity, there is no any information of allergenic properties of silver, and patients also have good acceptability. All of these characteristics promotes heightened interest to silver in many countries all over the world.
Microphoto of silver nano particles
Why nano silver is better than antibiotics?After long period of usage the therapeutic value of synthetic antibiotics has decreased because of appearance of microorganisms tolerant to it. Development of resistibility of microorganisms to antibiotics can occur by the reason of direct mutation of a microorganism, and also because of acquisition of DNA parts from other organisms. During millennia bacterias and viruses are not capable to develop "immunity" against silver. While silver is completely safe for mammals (including the human), reptiles, plants and all other organisms which have a multicellular structure.
Silver actions are specific not on an infection (as at antibiotics), but on cellular structure. Any cell without chemically steady wall (such cellular structure have bacterias and other organisms without a cellular wall, for example, cell-free viruses) is subject to silver influence. As cells of mammals have a membrane of absolutely other type (not containing peptidoglycans), silver does not effect on it in any way.
In general the mechanism of struggle of silver against monocelled (bacteria) and cell-free microorganisms (viruses) represents the following: silver reacts with a cellular membrane of a bacteria which represents a structure made from special proteins (peptidoglycans), connected by amino acids for providing mechanical durability and stability.
Silver co-operates with external peptidoglycans, blocking their ability of transferring oxygen in a bacteria cell that leads to “asthma” of a microorganism and its destruction.
Where to be applied?Within the main advantage of nano silver which was modified in a special way to keep biocidal properties, it is rational to use nano silver not as disinfectants of frequent application, but to add it in paints, varnishes and other materials that allows to save money, time and labour expenditures.
Water-based paint and enamels with nano silver have been tested on strong bacterias: the salmonella, Kokh's stick, Staphylococcus, Listeria, Enterococcus etc. As a result of the spent researches have been proved its high efficiency - at hit on a surface covered with such paint, concentration of bacteria decreases about 0,5-2 times at once, and the full destruction of a colony occurs within 2 hours.
At applying, the paint forms a thin, proof bactericidal cover with a wide spectrum of action. The covering of surfaces with such paints can be recommended not only to various educational and medical institutions, enterprises of food manufacture, food warehouses, places of a mass congestion of people and in other premises with the high epidemiological danger, but also in house or apartment usage, for example coverings of walls or ceilings in a children's room, on kitchen, in a toilet, a bathroom and so forth…
Paints can be applied to external and internal works, it work in a thin layer, forming a non-polluting, "breathing" covering. Having fine adhesion to beton, a tree, plaster, a brick, to plaster quickly dry up within 2 hours. The paints has no any fire and explosion hazards, to the contrary it become water-, weather-,light-proof. Paints with nano silver are harmless - do not contain toxic components and have no smell that allows to apply it in schools, nurseries, hospitals, kindergartens and other child care centers.
The products containing nano particles of silver are unique, because it suppress growth and enlargement of bacteria which are not only infection activators, but also SOURCES of UNPLEASANT SMELLS.
There are a plenty of zones where a serious epidemiological danger and fast propagation of virus diseases are occurs: the markets, hotels, stations, underground, stadiums and sports clubs, the trading and exhibition centers, cinemas, zoos, various medical and educational institutions, kindergartens and a day nursery - all places of a mass congestion of people. Here it is necessary to carry military barracks and prison premises, etc.
In the light of latest developments paint and varnish materials will be actual for use by poultry breeders for preventive processing of walls, ceilings and other designs at poultry packing houses and integrated poultry farms.
Property of sterility is especially actual for damp premises (refrigerating chambers, expeditions of finished goods of bread-baking complexes, storehouses of a flour, grain, groats, pools, baths, cellars etc.).
In medical institutions, in the enterprises of a treatment-and-prophylactic profile to lower microbic pollution, use disinfectant solutions with which process walls. But painting of the same walls by antimicrobic paints at which biocidal action remains not less than year, will allow to save considerably expenditures of labor and financial assets.
Besides, there is no possibility to wash out every day all premises (including CEILINGS) in medical institutions, schools, kindergartens, hairdresser's, baths, houses, apartments, in public transport and so forth with a solution of chloramines while to paint all these premises or at least its’ any separate fragments (ceilings, window, door, battery, handle and so forth) will be most effective.
Nano particles of silver can be used for modifying of traditional and creations of new materials, the coverings disinfecting and washing-up liquids (including tooth and cleaning pastes, detergent powders, soap), cosmetics. Coverings and materials (composit, textile, paint and varnish, carbon and others), modified with silver nano particles, can be used as preventive antimicrobic protection frames in places where danger of propagation of infections increases: transport, public catering enterprises, in agricultural and cattle-breeding premises, in nurseries, sports, medical institutions. It is possible to use nano particles of silver for water purification and destruction of pathogenic microorganisms in filters of central airs, in pools, bathrooms and other similar places of mass visiting.
Conclusions…Today the volume of world nano technology market is measured in billions dollars (while this market is made mainly by new materials and the powders improving properties of materials), and by 2015, under forecasts of the western experts, it will exceed $1 bln. In the near future economic, military, social and political position of the developed countries will be defined by a level of development of national nano industry.
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Comments
Usually we deal with powders which have sizes of particles tens or hundreds micron. Basically powders with particles in size more than 10 microns are used even in powder metallurgy. A human eye can see a point in 20 micron. The powders can have absolutely new characteristics.
Particles which have size from 1 to 100 nano meters usually identify like «nanoparticles». The area of nano sizes is transitional between amorphous and crystalline state of substances. In this area structured characteristics begin to play an important role in addition to size factor.
The change of fundamental characteristics of traditional materials in nano disperse condition (decrease: thaw point, heat of evaporation, ionization energy, electronic work function, etc.) discovers the broadest possibilities in the field of creation of the newest materials and technologies, conceptually new devices and instruments.
Nano particles of some materials have very good catalytic and adsorptive properties. Other materials show us surprising optical properties, for example, super thin films of organic materials which can be applied to production of flexible solar batteries.
One can share nano particles on 3 basic classes:
3-dimensional particles – particles received by explosion of conductors, plasma synthesis, restoration of thin films etc.;
2-dimensional objects— the films received by methods molecular layering, a method ionic layering etc.;
1-dimensional objects — nano fibers
Nano composites — the materials received by injection of nano particles into any matrixes.
Nano materials – the materials, which has structured fragments from 1 to 100 nanometers.
Our technological
process.
In a basis of our technology the phenomenon of wire electrical explosion (WEE) is necessary. Through a piece of metal wire (foil) impulse of current is put through and under its influence the wire bursts into finest particles and stream. When scattered at great speed, products of destruction quickly cool down and form nanosized powders (NP). Technological process is carried out in isolated spaces, without use of harmful chemical substances and with small expenditure of inert gases. Besides, gas expenditure is mainly connected not with powder production, but with its transportation, packing and other further operations. Depending on the sort of gas, surrounding the destroyed wire, it’s possible to receive powders of metals, alloys, powders of chemical combinations or compositional structures. Thus, separate particles are composite.
Characteristics of our powders.
Dispersion of a powder, structure (architecture) of particles and other characteristics are defined by parameters of a digit contour, a material and the geometrical sizes of a wire (foil) and characteristics of the gas environment in which explosion is made. Size distributions of the particles received by electro explosive technology, tend to submit to a logarithmic variant of the normal law of distribution. All a particle, received on our technology, have the spherical form. In certain cases particles with poorly expressed facet can be formed. As the process of formation of particles occurs in no equilibrium conditions, a structural and phase heterogeneity (polymorphism) become its’ characteristics. Powder particles are formed from the incoherently-packed blocks (structural fragments) in the size range from 20 to 40 nanometers.
The crystal lattice of blocks is deformed in no small degree. Some quantity of metal is in disorder (a X-ray - amorphous) condition that allows to carry considered object to the systems which structure is intermediate, between crystal and amorphous. At heating of such structure to certain temperature (sometimes temperature is only 40 – 50○С) the process of crystallization accompanied by
allocation of free energy begins.
The basic characteristics which distinguish electro explosive powders from others:
- Very low temperatures of sintering. The silver powder conglomerates at temperature
nearby 70°С;
- Stability of electrophysical properties in the field of low temperatures;
- High chemical activity. At achievement of threshold temperatures (200-500) °С chemical activity increases repeatedly;
- High value of factor of absorption of electromagnetic radiation in a wide range of
frequencies.
- The lowered work of an exit of electrons;
- Presence of the superfluous (reserved) energy.
Areas of possible applications of our production or where to search for consumers:
1. Small additives of nano powders raise characteristics of heavy-duty high density materials, for example (W-Ni-Fe);
special composite materials, for example (magnetic - Nd-Fe-B, superconductors -
Ba-Cu-O, Ba-Fe-O); improve mechanical characteristics of rubbers and polymers.
2. Electroconductive polymers, pastes, paints.
3. Gas absorbers and cathodes of gas-discharge lamps.
4. Alkali metal grease. Additives to oils. Materials with extremely low factor of a friction (WS2, MoS2);
5. Manufacture of technical corundum (polishing pastes, semiprecious stones).
6. Cluster and magnetic liquids. Cooling liquids.
7. Nano in technologies of water purification, water solutions, other liquids and gases. Filtering materials based on nano-fibers. Modification
of filtering materials and membranes.
8. Nano in medicine: drug delivery; new medical products based on nano particles as anticancer therapy; healing of burns and
wounds.
9. Sprayed cathodes and electro-contacting materials.
10. Components of solders with low temperature of the soldering and a high temperature of unsoldering for connection of diverse
materials (glass – metal; the semiconductor – metal; jewels – metal, etc.).
11. Nano particles of many materials (for example, silver) possess strong disinfecting effect. Release of materials, paints,
varnishes, the coverings possessing disinfecting characteristics, is necessary
for the food production, medicine, agriculture and other industries.
12. Composite pastes for laying of functional metal layers on various products, for example, solar energy converters.
13. Components of fuel, pyrotechnic structures and explosives.
14. Heat-producing elements and hydrogen generators and other gases.