FEATURES OF MOLECULAR AGGREGATION OF BLOCK COPOLYMER ON BASE OF STYRENE AND POLYETHYLENE GLYCOL IN SOLUTIONS

Abstract

This article focuses on the study of behavior of macromolecules of block copolymer on the base of styrene and polyethylene glycol in toluene media. Unique property of block copolymers is the ability of chemical heterogeneous blocks to phase separation. This process leads to the formation of micelle similar structures in selective solvents. These aggregates have the core from soluble block and the micelles capsule from insoluble block. Similar structures (reverse micelles) would be used for the purpose of stabilization of metal organosols. In this work aggregative stable reverse micelles in such systems as "toluene - water" and "toluene - methanol" have been prepared. Block copolymer of styrene and polyethylene glycol was applied as stabilizer in solutions with polymer concentration from 2.5 g/ 100 ml to 1 g/ 100 ml. Block copolymer has been synthesized by means of isocyanate cure on the end hydroxyl groups. Its structure has been confirmed by differential calorimetry spectroscopy (DSC) method. Dimension of formed particles has been determined by methods of sedimental turbidimetry and dynamic light scattering (DLS). Existence of both individual macromolecules and molecular aggregates in initial solutions has been established by DLS method. It has been found that dimensional homogeneity of organosol particles enlarges with the increase in dispersed phase content to 10 mass. %. At that, the size of the micelles in presence methanol is less than in water presence. Particles size also depends on polymer concentration in solution. The sizes of micelles in both systems increase with increasing concentration of the block copolymer, and with an increase in the content of the dispersed phase, a gradual decrease in their sizes is observed.  It was shown that the sedimentation turbidimetry method does not reflect the behavior of the copolymer molecules in solutions, which results in a large scatter of data on the determination of particle sizes of the organosol in the toluene-water system with a water content of less than 5 masses. % . Based on the data obtained, it is assumed that micelles stabilized by a block copolymer based on styrene and polyethylene glycol can be used to introduce metal particles into them, followed by the formation of a metal layer on a solid surface.