ИСТИНА

Amphiphilic ionic block copolymers in aqueous media self-assemble into micelles with hydrophobic core and ionic lyophilizing corona. Introduction of hydrophobic moieties into corona may trigger further segregation of corona onto ionic and hydrophobic domains thus outlining the way for design of micelles with multicompartment corona. Current presentation deals with the question of how the ratio of ionic and hydrophobic units and the manner of their distribution in corona (block vs. statistical) influence the structure and phase stability of micelles as well as their complexation properties. The procedure of obtaining polymer micelles with hydrophobic polystyrene core and amphiphilic corona from ionic N-ethyl-4-vinylpyridinium bromide units (EVP) and hydrophobic 4-vinylpyridine (4VP) units (pH 9) with various [EVP]/[4VP] ratio and distribution character was elaborated. It was shown that introduction of 4VP-units into PEVP-corona has no impact on micelle structure until its content reaches the value of ca. 30  40 mol.%. Further increase of 4VP-fraction is accompanied by compartmentialization of corona and drastic changes in micelle mass and structure. In the case of statistical distribution of 4VP and EVP units these changes are moderate in value and jump-like in character. Alternatively, in the case of block distribution of ionic and hydrophobic units structural changes are large in value but monotonous in character. The micelle dispersion stability and the ability to form stable micelle complexes with the oppositely charged polymeric (poly[methacrylic acid]) or amphiphilic (sodium dodecylsulfate) species follow the trends of micelle structural reorganizations upon variation of ionic and hydrophobic units in corona.