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results of experimental researches

It is authentically positioned, that at draining of solutions of cysteine and silver nitrate silver mercaptide (MS) as a result of replacement of atom of hydrogen in tiolnoj to group by silver [48] is formed.

It proves to be true a method infra-red (IK) spectroscopy on absorption band disappearance on the frequency of 2544 sm-1 responsible for valence vibrations tiolnoj of group (-SH) in a molecule of cysteine, sm fig. 1.7а. From fig. 1.7б follows, that carboxyl groups in TSSR are deprotonirovannymi while absorption bands of carbonyl groups (1710-1790 sm-1) are absent. Occurrence of hydrogen bridges result ins to significant expansion and decrease in intensity of absorption band in the field of centre frequencies that is more expressed in Ik - spectrums TSSR and gel. Presence of sulphates-ions at a hydrogel spectrum is observed in a range of 1130-1080 sm-1 that can serve as additional acknowledgement of not covalent linkage after addition of the initiator of gelation.

According to data ultra-violet (UF) spectroscopy process of maturing TSSR (a stage after mixing the component before introduction of the initiator of gelation) is accompanied by growth of absorption bands of around 310 and 390 nanometers (fig. 1.8). It is supposed, that these strips are connected with charge transfer between atom sulfurs (donor) and atom of silver (acceptor) of various particles MS that is accompanied by formation supramolekuljarnyh oligomers. Besides, particles MS in TSSR are zwitter-ions which can also assotsiirovat with superfluous ions of silver. It was revealed, that dilution TSSR result ins to reduction of intensity of strips 310

And 390 nanometers that can testify to dissociation supramolekuljarnyh aggregates. Thus it is impossible to explain presence of the specified strips plazmonnym a resonance at nanochastits silver which depending on their form and is observed the size on wave length of 391 nanometers and above [49].

Drawing 1.7 - Ik-spectra of the dry powder L-tsisteina (1) which frozen and have been dried up TSSR (2) and TSSR in gel state (3) in two ranges: a) 3750-2110 sm-1;) 1800­900 sm-1

Drawing 1.8 - Uf-spectra of absorption TSSR at a maturing stage: 1) 0; 2) 30; 3) 60; 4) 90; 5) 120 mines after mixing initial a component. T = 298.15 K (CL-cys = 3.0, CAgNo3 = 3.75 mmol/l)

Drawing 1.9 - Dependence of a shear modulus (1) and losses (2) TSSR (Сьсуз=3.0, CAgNO3 = 3.75 mmol/l) at addition Na2SO4 (CNa SO = 0.25 mmol/l) from time at T = 298.15 To and frequency ostsilljatsy 1 Hz

Potentiometric research of effects kompleksoobrazovanija has shown, that in capable to gelation TSSR (i.e. at rn ~ 3) the dominating form are bijadernye protonirovannye complexes Ag2HCys + which self-assemblage, probably, and result ins zhelirovaniju systems [50]. Value lg β (Ag2HCys +) = 27.28 yo 0.12 is found. It is possible to assume the following structure of complexes

That will quite be co-ordinated with literary data about propensity of silver derivative thiols to formation of polymeric chains at the expense of formation of donor-acceptor communications:


It is experimentally proved, that such structure have solid tsisteinat and other mercaptides of silver [51; 52].

Drawing 1.10 - Distribution of a diffusivity for TSSR depending on time

1) - 30, 2) - 122 mines, Cbcys = 2.7 mmol/l, CAgNO3 = 3.3 mmol/l.

During the made rheological tests of the synthesised hydrogels it has been positioned, that they possess thixotropic properties. At vigorous shaking of a test tube gel passed in a solution condition, and at a test tube finding in a rest condition again there was a gelation. Such procedure could be retried repeatedly. On fig. 1.9 data of rotational viscosimetry from which it is visible are presented, that at electrolyte addition in TSSR in due course there is an essential modulus reinforcement of system. After achievement of some critical value it was observed "having razed", i.e. falloff of an elastic modulus. Further ageing TSSR in a mode of poorly oscillating shear stress result ined to repeated increase of the elastic modulus, the subsequent failure etc. Such rheological behaviour is characteristic for thixotropic systems [53]. It is possible to assume, that at electrolyte introduction in TSSR the dimensional grid and a solution is formed passes in a gel condition. However this gel-grid is weak, therefore is comparative
Easily collapses under the influence of shear stress in a rheometer.

Researches.

Studying TSSR by a method of dynamic light scattering has shown, that in it the whole set klasterov from molecules MS of the various size (fig. 1.10) is observed. Thus with growth of time of standing TSSR the size klasterov increased. By means of the analysis of the size and a charge nanochastits it has been positioned, that klastery at a stage of maturing TSSR have positive charge that will be co-ordinated with results potentiometric TSSR, volume concentration of reagents of 0.07 %; TSSR, volume concentration of reagents of 0.005 %; GG, volume concentration of reagents of 0.07 %; GG, volume concentration of reagents of 0.07 %. Molarity Na2SO4 makes 0.8 mmol/l.

Drawing 1.11 - Electronic microphotos TSSR and hydrogel on its basis

On fig. 1.11 the electronic microphotos TSSR received by a method of translucent electronic microscopy (PEM), for samples of a solution of various concentration (fig. 1.11а,) and hydrogel are presented at different degrees of increase (fig. 1.11в,). From drawing it is visible, that TSSR consists of the separate spots-klasterov consisting of particles MS (fig. 1.11а). Stability klasterov in a solution is provided with their positive charge. In a gel-condition are observed niteobraznye crossed structures (fig. 1.11в), consisting of the same spots-klasterov. Depending on type of used electrolyte character of a dimensional grid of gel can change essentially [47], but always for any hydrogel method PEM had been fixed reticulate structures.

On fig. of 1.11 g as an example the grid of gel having structure of "horsehair" and formed at introduction in TSSR Na2SO4 is resulted. It is positioned, that the mesh
The structure in embryo occurs and in strongly diluted with TSSR without electrolyte addition (fig. 1.11). Thus TSSR possesses properties of weak physical gel. Thus, as a result of the made experimental researches it is positioned, that the considered system tends to the self-assemblage, characterised by formation of threadlike structures and grid strongly branched out gel-.

1.2.3.

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A source: Komarov Pavel Vyacheslavovich. MULTISCALE MODELLING NANODISPERSNYH of POLYMERIC SYSTEMS. The dissertation on competition of a scientific degree of the doctor of physical and mathematical sciences. Tver - 2014. 2014

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