Vodolazka N. Acidity and solvation in organized solutions: differentiating action of nanoparticles in lyophilic dispersions

Investigated objects: the protolytic equilibria of indicator dyes in both various types of organized media and true solutions. Purpose: to expand the conception about acid-base processes, solvation/binding of organic acids concerning the big group of molecular probes - indicator dyes - in both true solutions and various types of organized media. To find and to characterize the peculiarities of an influence of different nanosized systems on chemical equilibrium of reagents. To develop new approaches to purposeful change of parameters of ionic equilibria and spectral characteristics of indicators using various nanoaggregates and show the possibilities of an applied use of micellar surfactant solutions and different types of lyophilic systems. Methods and apparatus: spectroscopy; potentiometry; transmission electron microscopy; dynamic light scattering; cyclic voltammetry; X-ray diffraction. Theoretical and applied results: dispersed nanoscopic water inside reversed microemulsions differs from "usual" water by micropolarity and acidity and has differentiating action on reagents dissociation. The possibility of reaction of choline esterase's hydrolysis of fluorescent substrates was shown in micellar solution of zwitterionic sulfobetaine surfactant. The obtained stable polymeric ultrathin Langmuir-Blodgett films with indicator dyes can be used as pH-sensors many times. The synthesized ordered mesoporous organosilica materials with various hydrophobicity and adjusted chemical, mechanical, optical and electrical properties can be applied in electrochemistry, chromatography and catalysis. Novelty: all investigated nanosystems have strong differentiating action on dissociation of indicators. New type of tautomerism of 2,4,5,7-tetranitrofluorescein dianion in DMSO, 90% acetone and micellar solution of cationic surfactant. First it was found that about 10% of fluorescein monoanions in aprotonic dipolar solvents exist as phenolate tautomer. It was proposed to use apparent constants of indicators in micelles of zwitterionic sulfobetaine surfactant and in cationic micelles/microemulsions at strong shielding of surface charge as model of intrinsic constant of indicator for estimation of electrostatic potential values of charged surfaces of nanoaggregates by indicator method, the use of dissociation constants of hydrophobic dye N,N/-dioctadecylrhodamine is especially perspective. Field of the practical application: the results of dissertation are embedded in chemical faculty of V.N. Karazin Kharkov National University for special courses of lectures and laboratory exercises. Implementation degree: physical and colloid chemistry.