ИСТИНА

Self-assembly is a process of spontaneous formation of organized structures via non-covalent interactions of system components. Ionic amphiphilic diblock copolymers belong to self-assembling polymers. In aqueous media, they form micelles with insoluble hydrophobic core and lyophilizing ionic corona. A challenging task is a creation of hierarchically organized polymer micelles with their core or corona further subdivided onto smaller structural units different in properties and composition [1]. The present study deals with such type of polymer micelles with hydrophobic polystyrene (PS) core and ionic amphiphilic corona from charged N-ethyl-4-vinylpyridinium bromide (EVP) and uncharged 4-vinylpyridine (4VP) units, pH 9. Micelles spontaneously self-assembled from PS-block-poly(4VP-stat-EVP) macromolecules in aqueous media. The fraction of randomly distributed EVP-units in corona-forming block is =[EVP]/([EVP]+[4VP])=0.31.0. Structural characteristics of micelles as function of corona composition  have been investigated both experimentally and theoretically. All micelles possessed spherical morphology. The aggregation number, geometrical characteristics and electrophoretic mobility of micelles changed in a jump-like fashion near =0.60.7. This point means the compartmentalization of the corona at lower . Theoretical dependencies for micelle aggregation number, corona dimensions and the fraction of small counterions outside corona vs.  were deduced via minimization the expression for the micelle free energy, taking into account surface, volume, electrostatic and elastic contributions of chain units and translational entropy of mobile counterions. Theoretical estimations also point onto sharp structural reorganization at certain corona composition. The abrupt compartmentalization of micelle corona below =0.60.7 entails dramatic changes in micelle dispersion stability or their ability to form soluble complexes with oppositely charged polymeric (sodium polymethacrylate) or amphiphilic (sodium dodecylsulfate) complexating agents [2]. We believe the conducted research creates a robust foundation for design of multifunctional polymeric micelles, based on heterogeneity of their structure.