NASU A. V. Dumansky Institute of Colloid and Water Chemistry

Kiev, Ukraine

NASU A. V. Dumansky Institute of Colloid and Water Chemistry

Kiev, Ukraine

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Dan A.,Max Planck Institute of Colloids and Interfaces | Wustneck R.,Max Planck Institute of Colloids and Interfaces | Kragel J.,Max Planck Institute of Colloids and Interfaces | Aksenenko E.V.,NASU A. V. Dumansky Institute of Colloid and Water Chemistry | And 2 more authors.
Food Hydrocolloids | Year: 2014

The equilibrium and dynamic interfacial properties of β-casein (βCS) adsorbed at the water/hexane interface have been studied systematically over a wide range of pH. The results are analyzed in the context of a recently developed thermodynamic model, which is not only applied to characterize the adsorption behavior of βCS layers, but at the same time the visco-elastic properties of the surface layer. The equilibrium model can be adequately used for the adsorption layer when they are in a quasi-equilibrium state, however, it turned out that reliable information is provided only in the vicinity of equilibrium. Thus, the interfacial structure attained by the protein at the water/hexane interface resulting from the cohesive interaction between oil phase and the hydrophobic parts of the protein molecules is satisfactorily accounted in view of the results presented. The dilational viscosity of the adsorbed βCS layers is found to be very small and therefore, the interfacial layers behave essentially elastic. The analysis of the interfacial elasticity provides information on the conformational transitions within the interfacial layer. The selection of the model parameters is based on the slow structural change of βCS adsorption layers with increasing pH of the solution. The maxima encountered in the dynamic elasticity values even at pH 5, where βCS is in its most compact conformation, clearly suggest that the interfacial layer undergoes structural changes depending on the age of the adsorption layer. © 2012 Elsevier Ltd.


Fainerman V.B.,Donetsk Medical University | Aksenenko E.V.,NASU A. V. Dumansky Institute of Colloid and Water Chemistry | Mucic N.,Max Planck Institute of Colloids and Interfaces | Javadi A.,Max Planck Institute of Colloids and Interfaces | And 2 more authors.
Soft Matter | Year: 2014

On the basis of experimental data for the homologous series of alkyltrimethylammonium bromides (CnTAB) the equilibrium surface tension isotherms at three types of liquid-fluid interfaces are discussed: solution/air, solution/alkane vapor and solution/liquid alkane interfaces. It is shown that the adsorption characteristics can be described at all three interfaces by the same thermodynamic approach. In the presence of alkane molecules (in the liquid alkane phase or in the alkane vapor phase) the C nTAB adsorption layers can be best described by a co-adsorption of the alkane molecules. © 2014 the Partner Organisations.


Fainerman V.B.,Donetsk Medical University | Mucic N.,Max Planck Institute of Colloids and Interfaces | Pradines V.,CNRS Coordination Chemistry | Aksenenko E.V.,NASU A. V. Dumansky Institute of Colloid and Water Chemistry | Miller R.,Max Planck Institute of Colloids and Interfaces
Langmuir | Year: 2013

The adsorption of members of the homologous series of alkyl trimethylammonium bromides (CnTAB) is studied at water/alkane interfaces by drop profile analysis tensiometry. The results are discussed in terms of a competitive adsorption process of alkane and surfactant molecules. A thermodynamic model, derived originally for the adsorption of surfactant mixtures, is adapted such that it describes a competitive adsorption of the surfactant molecules from the aqueous phase and alkane molecules from the oil phase. This new model involves the interspecies attraction coefficient, which mutually increases the adsorption activities of the alkane and CnTAB. The effects of the alkyl chain length n of CnTABs and the influence of the number of C atoms in the alkane chain are discussed, and the physical quantities are compared to those determined at the aqueous solution/air interface. The new theoretical model for aqueous solution/oil interfaces is also compared to a theory that does not consider the adsorption of alkane. The proposed new model demonstrates good agreement with the experimental data. © 2013 American Chemical Society.


Dan A.,Max Planck Institute of Colloids and Interfaces | Wustneck R.,Max Planck Institute of Colloids and Interfaces | Kragel J.,Max Planck Institute of Colloids and Interfaces | Aksenenko E.V.,NASU A. V. Dumansky Institute of Colloid and Water Chemistry | And 2 more authors.
Langmuir | Year: 2013

The interfacial behavior of β-casein (βCS) has been investigated in presence of the cationic surfactant dodecyl trimethyl ammonium bromide (DoTAB) at the water/hexane interface and compared to that obtained for the water/air interface. The used experimental technique is a drop profile analysis tensiometer specially equipped with a coaxial double capillary, which allows investigation of sequential adsorption of individual components besides the traditional simultaneous adsorption of two species. This method also provides the dilational rheological measurements based on low frequency harmonic drop oscillations. The tensiometric results show that the equilibrium states of the mixed βCS/DoTAB layers built up on the two different routes do not differ significantly, that is, the general compositions of the mixed layers are similar. However, the results of dilational rheology for the two adsorption strategies are remarkably different indicating different dynamic characteristics of the adsorbed layers. These findings suggest that the respective mixed layers are more proteinlike if they are formed via sequential adsorption and more surfactant-like after simultaneous adsorption. In contrast to the W/A interface, at the W/H interface proteins remain at the interface once adsorbed and cannot be displaced just by competitive adsorption of surfactants. © 2013 American Chemical Society.


Dan A.,Max Planck Institute of Colloids and Interfaces | Gochev G.,Max Planck Institute of Colloids and Interfaces | Gochev G.,Bulgarian Academy of Science | Kragel J.,Max Planck Institute of Colloids and Interfaces | And 3 more authors.
Current Opinion in Colloid and Interface Science | Year: 2013

Mixed protein-surfactant adsorption layers at liquid interfaces are described including the thermodynamic basis, the adsorption kinetics and the shear and dilational interfacial rheology. It is shown that due to the protrusion of hydrophobic protein parts into the oil phase the adsorption layers at the water-hexane interface are stronger anchored as compared to the water-air surface. Based on the different adsorption protocols, a sequential and a simultaneous scheme, the peculiarities of complexes between proteins and added surfactants are shown when formed in the solution bulk or at a liquid interface. The picture drawn from adsorption studies is supported by the findings of interfacial rheology. © 2013 Elsevier Ltd.


Goncharuk V.V.,NASU A. V. Dumansky Institute of Colloid and Water Chemistry
Journal of Chemistry | Year: 2013

A comprehensive review on water as a buffer of the planet and its immune system is presented. The relationship between the quality of drinking water, the level of development of human intelligence, and its health is highlighted. The problems of obtaining cytogenetically and physiologically safe high-quality drinking water are discussed along with the problems of its decontamination. The solutions to maintain stable development of aquatic ecosystems are proposed. It is shown that tap water is the habitat of multiresistant genetically-mutated microorganisms. © 2013 Vladyslav V. Goncharuk.


Lysenko L.L.,NASU A. V. Dumansky Institute of Colloid and Water Chemistry
Russian Journal of General Chemistry | Year: 2014

The possibility of application of the modified electrokinetic treatment method to removal both inorganic and organic contaminants from clay soils has been demonstrated. The proposed improvements include the adjustment of pH of the soil pore solution, as this parameter is one of the major factors determining the treatment efficacy. The modification consists in replacement of the conventional acidic or alkaline reagents with neutral ones, thus enhancing the ecological compatibility of the detoxification process. © 2014 Pleiades Publishing, Ltd.


Goncharuk V.,NASU A. V. Dumansky Institute of Colloid and Water Chemistry
Journal of Chemistry | Year: 2013

The main positions of the new standard on drinking water are provided. The inconsistency of existing approaches to the assessment including methodology of drinking water quality was substantiated. The main advantage of the new standard is the inclusion of integral methods of water quality, universal for all kinds and types of toxic compounds, irrespective of their origin and nature of the action. © 2013 V. Goncharuk.


Savitskii D.P.,NASU A. V. Dumansky Institute of Colloid and Water Chemistry
Colloid Journal | Year: 2016

The rheological behavior of slurries of coal at different stages of metamorphism has been studied as depending on glycerol content in an aqueous dispersion medium. Increased viscosity and reduced polarity of water–glycerol solutions have been found to increase the shear stress and viscosity of coal slurries. The effective viscosity of the slurries has been revealed to decline at the same weight content of the dispersed phase with a rise in the stage of coal metamorphism (i.e., when passing from brown coal to anthracite). © 2016, Pleiades Publishing, Ltd.


Mucic N.,Max Planck Institute of Colloids and Interfaces | Javadi A.,Max Planck Institute of Colloids and Interfaces | Kovalchuk N.M.,Max Planck Institute of Colloids and Interfaces | Kovalchuk N.M.,NASU F. D. Ovcharenko Institute of Biocolloidal Chemistry | And 2 more authors.
Advances in Colloid and Interface Science | Year: 2011

Each experimental method has a certain range of application, and so do the instruments for measuring dynamic interfacial tension and dilational rheology. While the capillary pressure tensiometry provides data for the shortest adsorption times starting from milliseconds at liquid/gas and tens of milliseconds at liquid/liquid interfaces, the drop profile tensiometry allows measurements in a time window from seconds to many hours. Although both methods together cover a time range of about eight orders of magnitude (10 - 3 s to 10 5 s), not all surfactants can be investigated with these techniques in the required concentration range. The same is true for studies of the dilational rheology. While drop profile tensiometry allows oscillations between 10 - 3 Hz and 0.2 Hz, which can be complemented by measurements with capillary pressure oscillating drops and the capillary wave damping method (up to 10 3 Hz) these six orders of magnitude in frequency are often insufficient for a complete characterization of interfacial dilational relaxations of surfactant adsorption layers. The presented analysis provides a guide to select the most suitable experimental method for a given surfactant to be studied. The analysis is based on a diffusion controlled adsorption kinetics and a Langmuir adsorption model. © 2011 Elsevier B.V. All rights reserved.

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