Conquest of the nature by the person did not end yet. In any case, until we took a nanoworld yet and established in it the rules. Let’s look, what is it and what opportunities the world of the objects measured by nanometers gives us.
What is “nano”?
Achievements of microelectronics were once very famous. Now we passed to a new age of nanotechnologies. So such it is “nano” which then that began to be added to habitual words there, giving them new modern sounding: nanorobots, nanomachines, nanoradio and so on? The nano-prefix is applied in the International System of Units (SI). It is used for formation of designations of decimal submultiple units. It is one billion part of initial unit. In this case we speak about objects whose sizes are defined in nanometers. Means, one nanometer is a one billion part of meter. For comparison, the micron (it is the micrometer which gave the name to microelectronics, but also, microbiologies, microsurgeries etc.) is a one million part of meter.
If to take for an example millimeters (a prefix “miles -” – one thousand), then in millimeter of 1 000 000 nanometers (nanometer) and, respectively, 1 000 micrometers (micron). The human hair has thickness on average of 0,05-0,07 mm, that is 50 000–70 000 nanometers. Though diameter of a hair can also be written down in nanometers, it is yet not a nanoworld. Let’s go deep and will look what there is already now.
The sizes of bacteria average 0,5–5 microns (500–5000 nanometers). Viruses, one of the main enemies of bacteria, it is even less. Effective diameter of the majority of the studied viruses makes 20–300 nanometers (0,02–0,3 microns). And here the spiral of DNA has diameter more narrow than 1,8-2,3 nanometers. It is considered that the smallest atom is an atom of helium, its radius 32 пм (0,032 nanometers), and the biggest – cesium 225 пм (0,255 nanometers). In general, such object which size at least in one measurement is in the nanorange (1–100 nanometers) will be considered as a nanoobject.
Whether it is possible to see a nanoworld?
Of course, all it is told about, wants to be seen with own eyes. Well at least in an eyepiece of an optical microscope. Whether it is possible to glance in a nanoworld? In the routine way as we observe, for example, microbes, it is impossible. Why? Because it is possible to call light with some share of convention nanowaves. A wavelength of violet color with which the visible band begins, – 380–440 nanometers. A wavelength of red color – 620–740 nanometers. Lengths of waves of visible radiation make hundreds of nanometers. At the same time permission of routine optical microscopes is limited to the diffraction limit to ABBA approximately at the level of a half of a wavelength. The majority of the objects interesting us are even less.
Therefore the invention of a translucent supermicroscope became the first step on the way of penetration into a nanoworld. And the first such microscope was created by Max Knoll and Ernst Ruska in 1931. In 1986 for its invention the Nobel Prize on physics was handed. The principle of work same, as well as at a routine optical microscope. Only instead of light the cathode rays which is focused by magnetic lenses goes to the interesting object. If the optical microscope gave increase approximately in one thousand times, then electronic is million times more narrow. But it has also shortcomings. First, it is need to receive rather thin exemplars of materials for work. They have to be transparent in an electron stream therefore their thickness varies within 20–200 nanometers. Secondly, is what the exemplar under the influence of electron beams can decay and become useless.
Other option of the microscope using a cathode rays is the scanning supermicroscope. It does not illuminate an exemplar as previous, and scans it an electron beam. It allows to study “thicker” exemplars. Processing of the analyzed exemplar an electron stream generates secondary and obratnootrazhenny electrons, seen (cathodeluminescence) and x-ray radiations which are caught by express detectors. On the basis of the obtained data idea of an object is also formed. The first scanning supermicroscopes appeared in the early sixties.
The scanning probe microscopes – rather new class of the microscopes which appeared in the 80th years. Already made mention Nobel Prize on physics of 1986 was divided between the inventor of a translucent supermicroscope Ernst Ruska and creators of the scanning tunnel microscope Gerd Binnig and Heinrich Rorer. The scanning microscopes allow not to consider rather, and “to feel” an exemplar surface relief. The obtained data then will be transformed to the image. Unlike the scanning supermicroscope, probe use the sharp scanning needle for work. The needle which edge has thickness only several atoms acts as the probe which is brought on minimum distance to an exemplar – 0,1 nanometers. During scanning the needle moves over an exemplar surface. Between a needle and a surface of an exemplar there is tunnel current, and its size depends on distance between them. Changes are fixed that allows on their basis to construct the card of heights – the graphic representation of a surface of an object.
The similar principle of work uses also other microscope from a class of the scanning probe microscopes – atomic-powered. There is both a needle probe, and similar result – the graphic representation of a relief of a surface. But not the size of current, and power interaction between a surface and the probe is measured. First of all Van der Waals forces, but also and resilient forces, capillary forces, adhesive forces and others are meant. Unlike the scanning tunnel microscope which can be applied only to a research of metals and semiconductors atomic-powered allows to study also dielectrics. But it not its single advantage. He allows not only to glance in a nanoworld, but also to manipulate atoms.
Molecule pentaprice. And – molecule model. In – the image received by the scanning tunnel microscope. With – the image received by an atomic-powered microscope. D – molecules (ASM). And, B and C in one scale. / © Science
In the nature on a nanolevel, that is at the level of atoms and molecules, there is a set of processes. We can affect, of course, and now on how they proceed. But we do it almost blindly. Nanocars is an address tool for work in a nanoworld, it the devices allowing to manipulate individual atoms and molecules. Until recently only the nature could create them and operate them. We in a step of that day when too we are able to do it.
What can nanocars? Let’s take, for example, chemistry. Synthesis of chemical combinations is based that we create necessary conditions for course of chemical reaction. As a result at the exit we have a certain substance. In the future chemical combinations can be created, figuratively speaking, in the mechanical path. Nanocars will be able to connect and separate separate atoms and molecules. Chemical bonds will be formed as a result or, on the contrary, the available communications will be torn. Nanocars builders will be able to create molecular designs necessary to us from atoms. Nanorobots chemists – to synthesize chemical combinations. It is break in creation of materials with the given properties. Simultaneously it is break in environment protection. It is simple to assume that nanocars – the fine tool for processing of a wastage which in routine conditions difficult give in to utilization. If to speak about nanomaterials. The further technical progress comes, the it is more difficult to cope to a surrounding medium with its results. Too long there is a decomposition in the environment of the new materials which are thought up by the person. All know how the thrown-out plastic packages – a product of the previous scientific and technological revolution long decay. What will be with nanomaterials which will be garbage sooner or later? The same nanocars will have to be engaged in their processing.
Scientists speak about mechanosynthesis for a long time. It is chemical synthesis which is carried out thanks to mechanical systems. Its advantage seems that it will allow to position reactants with a fine precision. Here only when there is no tool which would allow to carry out it efficiently. Of course, the atomic-powered microscopes existing today can act as such tools. Yes, they allow not only to glance in a nanoworld, but also to operate with atoms. But they as macrocosm objects not in the best way are suitable for mass use of technology that cannot be told about nanocars. In the future on their basis will create the whole molecular conveyors and nanofactories.
But already now there are whole biological nanofactories. They exist in us and in all live organisms. Here therefore expect breaks in medicine, biotechnologies and genetics from nanotechnologies. Having created simulated nanocars and having introduced them in living cells, we can achieve impressive results. First, nanocars can be used for address carrying of medicinal preparations to the necessary body. We should not take medicine, understanding that only a part it will get to sick body. Secondly, already now nanocars undertake functions of editing a genome. The CRISPR/Cas9 technology spotted at the nature allows to make changes to a genome of both monocelled, and higher organisms, and including the person. And it is not only about editing a genome of embryos, but also a genome of live adult organisms. Also nanocars will be engaged in all this.
If nanocars is our tool in a nanoworld, then they somehow need to be operated. However, and here something in essence new should not be thought out. One of the most probable ways of management is radio. The first steps are already taken in this direction. Scientists from National laboratory of Lawrence in Berkeley led by Alex Zettl created the radio receiver from only one nanotube with a diameter about 10 nanometers. And the nanotube acts at the same time as the antenna, the selector, the amplifier and the demodulator. Can accept the nanoradio receiver both FM, and AM of a wave with a frequency from 40 to 400 MHz. To use the device, according to developers, it is possible not only for reception of a radio signal, but also for its transfer.
As a test signal music of Eric Clapton and the Beach Boys group served. Scientists transmitted a signal from one part of the room to another where there was a radio created by them. As it appeared, quality of a signal was rather good. But, naturally, mission of such radio receiver not listening of music. The radio receiver can be used in a set of nanodevices. For example, in the same nanorobots suppliers of drugs which will make the way to the necessary body for a blood-groove.
Creation of materials with properties which could not and be presented earlier, – one more opportunity which to us is given by nanotechnologies. To be considered “nano”, material has to have one or several sizes lying in the nanorange. Or to be created with use of nanoparticles or by means of nanotechnologies. Classification of nanomaterials most convenient for today – on dimension of building blocks of which they consist.
Zero-dimensional (0D) – nanoclusters, nanocrystals, nanodispersions, quantum points. Any of the parties of 0D-nanomaterial does not exceed the limit of nanorange. These are materials in which nanoparticles are isolated from each other. The first complex zero-dimensional structures received and put into practice are fullerenes. Fullerenes are strongest antioxidants from known today. In pharmacology pin hopes for creation of new drugs on them. Derivants of fullerenes well prove to be in treatment of HIV. And during creation of nanocars fullerenes can be used as details. The nanocar with fullerene wheels on the image is higher.
One-dimensional (1D) – nanotubes, fibers and bars. Their length makes from 100 nanometers to tens of micrometers, but diameter keeps within nanorange. The most known one-dimensional materials are nanotubes today. They have unique electric, optical, mechanical and magnetic characteristics. In the nearest future nanotubes have to find application in a molecular electronics engineering, biomedicine, in creation of new heavy-duty and extralight composites. Nanotubes and as needles in the scanning tunnel and atomic-powered microscopes are already used. It was told about creation on the basis of nanotubes of nanoradio above. Well and, of course, on carbon nanotubes the hope as is laid on material for a cable of the space elevator.
Twodimensional (2D) – films (covering) of nanometer thickness. It is all the known decanter – twodimensional allotropic modification of carbon (for a decanter the Nobel Prize on physics for 2010 is handed). Less known to the public силицен – twodimensional modification of silicon, фосфорен – phosphorus, германен – germanium. Last year scientists created борофен which, unlike other twodimensional materials, turned out not flat, but corrugated. The arrangement of atoms of pine forest in the form of corrugated structure provides unique properties of the received nanomaterial. Borofen applies for leadership in durability on stretching among twodimensional materials.
Twodimensional materials have to find application in an electronics engineering, during creation of filters for a desalting of ocean water (graphene membranes) and creation of solar batteries. Already in the nearest future the decanter can replace indium sesquioxide – infrequent and expensive metal – by production of touch screens.
Three-dimensional (3D) nanomaterials are powders, fiber, multilayer and polycrystalline laminates in which above-mentioned zero-dimensional, one-dimensional and twodimensional nanomaterials are building blocks. Densely adjoining to each other, they form among themselves interfaces – interfaces.
There will pass a little more time and nanotechnologies – technologies of manipulation with nanodimensional objects will become the habitual phenomenon. Just as technologies of microelectronics the computers which presented to us, mobile phones, satellites and many other attributes of the modern informational era became habitual. But influence of nanotechnologies on life will be far broader. We are expected by changes practically in all fields of activity of the person.