Summary_eng (Статистическое описание многочастичных эффектов в классических ион-молекулярных системах), страница 2

Nevertheless, thisopens pretty wide range of perspectives for applications: pharmacology (control of the drug compounds concentration in the polymer volume by the change of the eld strength), robotics (polymermaterials for the production of the articial muscles), textile industry (increase of the eectivenessof the polymeric ber dyeing in the electric eld) and so on. From fundamental point of view, itis interesting to theoretically investigate the conformational behavior of a single dielectric polymerchain in constant uniform electric eld, which monomers are isotropically polarizable molecules.

Itis important to note, that till recently in the world literature there have not been made any eortsto theoretically analyse such system even at the level of primitive Flory-de Gennes mean-eld typemodels. From the fundamental point of view the following questions must be answered.ˆ Is it possible to de-collapse a dielectric polymer globule with isotropic polarizable monomersby the electrostriction eect?ˆ How does a polarizability value of the monomer inuence on the behavior of such transition?ˆ Is it possible to control concentration of polarizable particles of some low-molecular targetcompound within the volume of polarizable polymer chain in dilute solutions by the electriceld change?To answer the raised questions, one has to formulate the simplest theoretical Flory-de Gennes typemodel of the polarizable polymer chain in the medium of the liquid solvent in the constant uniformelectric eld and generalize it in the case of the polarizable molecules of target compound presencein the bulk phase.Goal of the work.

To develop approaches for the description of the thermodynamic andstructural properties of ion-molecular systems (such as electrolyte solutions, ionic liquids, zwitterionsand dielectric polymers) in the bulk and at the interfaces, accounting for characteristics of theirmolecular structure (dipole moment, polarizability, eective size, parameters of specic interactions,etc.) from the rst principles of classical statistical mechanics.For the achievement of the goal following problems were posed.ˆ To develop formalism, based on the classical density functional theory and functional integrals,allowing one to obtain self-consistent eld equations, which reect presence of the solventmolecules in the electrolyte solution, carrying constant dipole moment and/or polarizability.ˆ To formulate, using obtained self-consistent eld equation, theory of the electrical doublelayer at the metal electrode/liquid electrolyte interface with account for polar or polarizablemolecules of the co-solvent.

To study, basing on the developed theory, a behavior of thedierential electric capacitance of the electrical double layer, depending on the values of dipolemoment, polarizability of co-solvent molecules and its concentration, and also on the specicinteractions between the components of the mixture.ˆ To develop a nonlocal eld-theoretic model of the electrolyte solution with a small additives ofthe polar particles with polar groups, located at suciently large uctuating distances betweeneach other. To derive, within formulated model, the self-consistent eld equation, generalizing well-known Poisson-Boltzmann-Langevin equation, for electrostatic potential, created byexternal charges in the electrolyte solution in presence of the particles with suciently largedipole moments.

To obtain a general expression for the electrostatic free energy of the electrolyte solution with the additive of the considerably long polar particles within the frameworkof Gaussian approximation.ˆ To construct a Flory-de Gennes type model of the weak polyelectrolyte macromolecule withaccount for the many-body dipole correlations of the monomers. To investigate, within the4developed model, a coil-globule transition of the weak polyelectrolyte chain, induced by dipoledipole interactions of the monomers, including many-body eects. To compare theoretical andMD simulation results.ˆ To develop a Flory-de Gennes type model of the exible dielectric polymer chain with anisotropically polarizable monomers, dissolved in the liquid dielectric in the uniform electriceld. To investigate conformational behavior of the exible dielectric polymer chain in theconstant uniform electric eld in the regimes of good and poor solvents.ˆ To develop a model of the dielectric polymer chain with the isotropically polarizable monomersin the medium of the dielectric solvent with a small additive of polarizable particles of thelow-molecular target compound in the constant uniform electric eld.

To investigate, inthe framework of developed model, behavior of the local concentration of the low-molecularparticles within the polymer volume depending on the relation between the polarizabilities ofthe monomers and molecules of target compounds.Research methodology.During the execution of thesis, modern methods of equilibriumstatistical mechanics have been utilised, such as methods of functional integration, classical densityfunctional theory and self-consistent eld theory.Main results, carried out to defence and their scientic novelty.ˆ Generalizations of the well-known theories of the electrical double layer at the metal/electrolytesolution interface have been formulated for the rst time, taking into account presence ofthe polar/polarizable particles of the co-solvent in the solution.For the rst time the behavior of the dierential capacitance of the electrical double layer with the increase of the dipolemoment and/or polarizability of the co-solvent molecules has been investigated.ˆ A new formalism has been formulated, based on the classical density functional theory, allowing one to obtain the self-consistent eld equations for the electrostatic potential, consideringpresence of the polarizable/polar particles of the impurity (co-solvent) in the electrolyte solution.ˆ A new formalism has been represented, based on the classical density functional theory, describing the electrical double layer at the metal/ionic liquid interface with a small additiveof the polar solvent with account for the short-range specic interactions between the compounds of the mixture.

For the rst time an explanation has been oered of the dierentialcapacitance behavior at the ionic liquid/charged electrode interface with increase of the waterconcentration within the volume of the ionic liquid, observed experimentally. The inuenceof the short-range specic interactions between the ions and molecules of polar solvent on thedierential capacitance of the electrical double layer has been systematically investigated forthe rst time.ˆFor the rst time a self-consistent eld theory of the electrolyte solutions with an admixture of the particles with uctuating distance between polar groups has been formulated,generalizing the well-known Poisson-Boltzmann-Langevin theory. For the rst time theself-consistent eld equation for the electrostatic eld potential, formed by external charges inthe electrolyte solutions with the addition of polar particles, has been obtained.

Within theGaussian approximation for the rst time the general expression for the electrostatic freeenergy of the electrolyte solution, dened by the thermal uctuations of the local electrostaticpotential near its zero value, with the addition of the polar particles has been obtained. Ithas been shown, that in the presence of the electrolyte ions in the solution, electrostatic freeenergy of polar particles, dened as an integral over vectors of the reciprocal space, convergesat the ultraviolet limit.ˆFor the rst timethe Flory-de Gennes type model of the exible polymer chain withmonomers, carrying constant dipole moments, accounting for the dipole correlations at the5many-body level, has been developed.

Within the developed model new regimes of the conformational behavior of the dipolar polymer chain have been discovered. For the st timea good agreement between the theoretical predictions and the results of the MD simulationshas been achieved.ˆ A new model of the dielectric polymer chain with isotropically polarizable monomers in theconstant uniform electric eld has been developed. Within the elaborated model the globulecoil transition, induced by the external electric eld, has been predicted for the rst time.ˆFor the rst time the model of the dielectric polymer chain with isotropically polarizablemonomers in the medium of liquid-phase dielectric solvent in the presence of the isotropicallypolarizable molecules of the target compound has been developed. For the rst time it hasbeen shown the possibility to control the conformational state of the dielectric polymer bythe change of the electric eld strength.

For the rst time the possibility of impregnationof the polarizable polymer chain with the particles of the target compound in the medium ofthe liquid dielectric has been theoretically justied.Theoretical signicance of the work consists in the development of the new approachesfor the description of the thermodynamical properties of ion-molecular systems in the bulk andphase boundary with the account for their molecular structure specics from the rst principles ofstatistical physics.Practical signicance of the work consists in the fact that developed approaches couldbe used for the fast and eective analysis of the thermodynamical properties behavior of the realion-molecular systems in dierent elds, such as electrochemistry, colloid chemistry, pharmacology,industry of the smart materials production, etc.Individual contribution of the author consists of the formulation of the problems, modelsdevelopment, performance of the analytical and numerical calculations, analysis of the obtainedresults and completion of the publications.The main content of thesisIn Introduction relevance of the thesis and authenticity of the obtained results are claimed,goal and problems of the project, main results, carried out to defence, scientic novelty, practicaland theoretical importance were formulated, and also research methods were described.Chapter 1Part 1.1Poisson-Boltzmann (PB) equation, being one of the simplest and, at the same time, the mosteective theoretical tools for the determination of the equilibrium distributions of the chargedparticles concentrations near the charged surfaces, nowadays found a wide range of applications insuch areas, as colloid chemistry, electrochemistry, biophysics, etc.

However, PB equation containsseveral assumptions, which do not allow one to apply it for a quantitative description of the ionicequilibriums in the real physical-chemical systems. Indeed, PB equation, while based on the meaneld approximation, does not take into account eects of the ionic correlations, and at the same time,simulation of the solvent as a continuous medium makes it impossible to consider eects, associatedwith its molecular structure.