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Unique research stand «Physic chemistry of the surface of micro- and nano- dispersed systems»

At the level of micro- and nanostructures, the durability of the structural connections is defined by physicochemical interaction of the component parts in all phases of the composite formation. The main role in these processes is played by the surface of the dispersed materials which is different to content due to heightened energy potential. Thus the main criterion in management of processes of the quality formation of the construction composites, considering the condition of the dispersed raw materials surface, is free surface energy of the system, for the experimental determination of which the Unique research stand «Physic chemistry of the surface of micro- and nano- dispersed systems» (URS PhChSNS) is created in the Northern Arctic Federal University in the Department of Compositional Materials and Constructional Ecology.

Unique research stand PhChSNS is the complex of modern mutually complementary science-intensifying equipment designed for the studies of physical and chemical characteristics and surface phenomenon at the border of division of phases in the micro- and nano- dispersed systems.

The key parameter, which is defined in the result of the experiments in which the unique research stand PhChSNS is used, is free surface energy of the solid body (critical value of surface tension of micro- and nano- systems, the value of complex Gamaker constant). Instrumental equipment of the unique research stand PhChSNS is directed, first of all, into the complex solution of this problem: the obtaining of nanomaterial, the control of the dispersion degree, of particles` form and size, of specific surface area, the determination energy characteristics and the observation of the conglomeration process in produced nanocomposite models. Moreover, the appliances included into the unique research stand PhChSNS can be successfully used to solve individual expertise and analytical tasks. For example, the determination of granulometric structure of bulk material over the wide range of dispersion (from nm to mm), of selection of sorption methods of water preparation, of determination of adhesive characteristics of the structural materials surface, the study of the influence of alternating temperatures on physical and mechanical properties of materials, etc.

The unique stand «Physical chemistry of the surface of micro- and nano- dispersed systems» consists of:

Planetary ball grinder РМ-100 (Retsch): obtaining of micro- and nano- 

dispersed material by the mechanical dispersion method 

Colloid grinder IKA magis LAB: improving the efficiency of the process of mechanical dispersion by mechanical and chemical activation

Vibratory grinder МВ-20: obtaining of micro- and nano- dispersed samples of rocks by the method of mechanical and chemical activation, with the weight of samples up to 10 kg

Particles size and charge analyzer DelsaNano C Zeta Potential/Submicron Size Analyzer: particles size determination (from 1 nm to 10 micrometers), fractional distribution, measurement of zeta-potential of suspension particles surface

Laser particle size analyzer Lasentec D600L и S400E with the system of laser video microscopy V819: visual description of the particles form and size in the real-time operation mode, particles size identification (from 500 nm to 1 mm), fractional distribution

Automatic analyzer Autosorb-iQ-MP: identification of specific surface and holes sizes in coarsely-, micro- and nano- dispersed conditions

Laser system for the measuring of the contact angle KRUSS Easy Drop DSA20E: identification of the critical value of the surface tension, wetting corner, lyophilic nature, lyophoby of the surface, adhesion of samples in coarsely-, micro- and nano- dispersed conditions

Hot-Cold BoxТХВ-64: samples test in the phases freezing-unfreezing over the range of temperature +700С ÷ -700С

In this part, authors would like to illustrate the resources of the unique stand for solving important analytic problems in the constructional materials science, which are to be solved with the use of dispersed raw materials.

Testing of the granulometric structure of the construction sand in the superfine condition. The granulometric structure of the construction sand in the superfine condition, after dispersion with Vibratory Grinder МВ-20 (fig. 1), is defined on the submicron particles size analyzer Delsa Nano (by the photon-correlation spectroscopy method) and on the Laser particle size analyzer Lasentec S400E with the system of laser video microscopy PVM V819 (analysis focused ray reflection method) (fig. 2-6).

For the particles size identification on the submicron particles analyzer Delsa Nano the method of photon-correlation spectroscopy, based on the principle of the dynamical light dispersion, is used. What is this method about? When the particles are illuminated with the laser, light dispersion is happening in all directions. This dispersed light comes into being from the system of dispersing elements in some content and depends on corners of registration and characteristics of apertures. This intensity of dispersed light will be result of the light overlap, dispersed by every element, in any condition and so will depend on comparative position of these elements.

Figure 1 — The preparation of the test sample:
a — Vibratory Grinder МВ 20-1.5; b — the division into fractions and test sample of sand

a b
Figure 2 — The equipment for particles measuring: 
a — the submicron particles size analyzer Delsa Nano; b — the laser particles size analyzer Lasentec
D600E (FBRM) with the system of
 laser video microscopy V819

Figure 3 — The window of the computer-assisted software engineering for particles sizes
measuring on
 the submicron particles size analyzer Delsa Nano

Figure 4 — Diagram of the dependence of particles amount on their sizes — exposures from the sample test report 

on the sand particles size measuring, with the average particle size 483±39 нм

Figure 5 — The window of the computer-assisted software engineering for particles size
measuring on
 the laser particles size analyzer Lasentec D600E with the method FBRM

Figure 6 — Photo of the observable sand sample, taken with the help of the laser video
microscopy system PVM V819:
a — before dispersion; b — after dispersion

When particles are moving, their relative position is changing; we can see the fluctuation of the intensity of a dissipated light. Under the effect of the Brownian force the particles are moving chaotically, therefore the fluctuations of the intensity of a dissipated light are random. For the small spinning particles, the fluctuations happen quickly, for the large and slower particles, the fluctuations happen slower.

Through the process of the change, the intensity of a dissipated light is registered as a sequence of data about the quantity of light pulse for the period ∆τ or as the quantity of the counting periods (quantity of such pulse) between two light pulses. The first method is the method of the temporary realm (more proper for the analysis of large particles); the second one is the method of the time frame (more proper for the analysis of small particles). The use of both methods permits to analyze the particles over the broad range of sizes from 0.6 nm to 7 micrometers.

To measure the sizes and for the calculation of the quantity of particles in real-time operation mode in the process fluid, where the suspended particulate matter`s concentration is high, we use the method of Focused Beam Reflectance Measurement (FBRM), which is realizing with laser scattering particle size distribution analyzer Lasentec D600E. D600E sounder can be placed into the environment of any concentration and any viscosity. A narrow laser ray focused on the surface of the opening passes through the sapphire opening of the sounder. This focused ray actualizes circular scanning around the circumference of the sounder opening. The particles movement doesn`t have any influence on the dimension accuracy because of high speed of circular scanning.

The focused laser ray is cutting the border of the particle, passing nearby the surface of the sapphire opening. The surface of particle is reflecting the ray backwards. The reflection is going on till the focused laser ray obtains opposite particle`s border. Optical instrument of the sounder D600E picks reflected rays and transforms them into electrical signal.

There is a special selective scheme for identification of the duration of the ray reflection in time of its movement from one particle to another in this method. The result of the multiplication of this value of duration and the scanning speed is the distance or so-called chord length. The chord is a line segment, connecting any two points at the border of the particle or particles formation. The method FBRM provides the dimension up to tens of thousands chords per second, this dimension allows getting certain particles distribution along the length of the chord. The distribution of the chord lengths is unique in essence for any current sizes and forms distribution. If the particle`s form, neutralized throughout millions of particles, is considered as the constant magnitude, the changes in chord length distribution will be connected only with sizes changes and particles amount changes. The data is accumulating and is being reflected in the program`s window as dependences and tabular information. The use of this method allows the measurement of particles sizes over the range of from 0.5 to 2500 micrometers.

The results of sand particles size measurement in superfine condition carried out with the analyzer Delsa Nano are presented in table 1.

Table 1 — The description of the fractions of the sand sample in superfine condition made with the analyzer Delsa Nano

Grade time t, min Fractions size, nm / Substance, %
Medium-size, nm
480 438.5/ 8.5 450.1/ 20.6 750.2/ 10.6 462.1/ 11.8 474.3/ 12.0 486.9/ 11.4 499.8/ 10.1 513.0/ 8.4 483.0 ± 39.4

The processed results of size and amount determination of particles of test sand sample, received with the help of laser scattering particle size distribution analyzer Lasentec D600E with the examination system of focused ray FBRM, are presented in the table 2. In determining the size and number of particles, the mass of test samples was taken for identical and equal to 0.05 g of the dry substance.

Table 2 — The numerical description of the fractions of various sand samples in superfine condition made with the analyzer Lasentec D600E

Grade time t, min Particles amount over the range, micrometers., piece./ Substance, % 
480 300-500150-300 50-150 10-50 5-101-5 0.5-1
0.11/0.01 0.05/ 0.00 3.21/ 0.36 227.64/ 25.21 220.63/ 24.43 451.25/ 49.98 0.00/ 0.00

The results received from the fractional particles distribution of sizes in two different methods show that the first method gives proper results for dispersion systems, which conserve kinetic stability and do not sedimentate temporally (dimensional, ultra micro dispersed systems). The second method (where the forcing agitation of analyzed suspension is used) gives proper results for micro- and coarsely- dispersed materials. Optimally it would be better to combine both methods to get the more complete picture of fractional denominate distribution.

Submicroscopical analysis. In figures 7 and 8, the results of video monitoring of structure formation in concrete of the control (with the micro dispersed sandy filler) and basic compositions at age of 28 days, received with the help of laser video microscopy system PVM V819.

Figure 7 — Photos of destroyed concrete samples of control

Figure 8 — Photos of destroyed concrete samples of basic composition

The use of the unique stand allows the successful solving of fundamental scientific problems in structural materials science, connected with the study of management resources of the quality formation of the structural composites considering the surface condition of the dispersed crude.

Дата изменения страницы 16.05.2013