TY - JOUR

T1 - Self-assembly of an amphiphilic diblock copolymer in aqueous solutions

T2 - Effect of linear charge density of an ionogenic block

AU - Kulebyakina, A. I.

AU - Lysenko, E. A.

AU - Chelushkin, P. S.

AU - Kabanov, A. V.

AU - Zezin, A. B.

N1 - Funding Information: 1This work was supported by the Russian Foundation for Basic Research (project no. 06 03 90153 NNF_a) and the Ministry of Education and Science of the Russian Federation (State Contract 02.740.11.0266).

PY - 2010/6

Y1 - 2010/6

N2 - The effect of linear charge density of the ionogenic block on the self-assembly of the amphiphilic diblock copolymer based on polystyrene and poly(4-vinylpyridine) partially alkylated by ethyl bromide in aqueous solutions at pH 9 is studied by UV spectrophotometry and dynamic and static light scattering. During dispersion in water, the diblock copolymer forms micelles composed of the hydrophobic polystyrene core and the amphiphilic lyophilizing corona consisting of N-ethyl-4-vinylpyridinium bromide ionic units and uncharged units of 4-vinylpyridine. It is shown that with a change in the fraction of charged units in the lyophilizing block from 30 to 90 mol %, the thermodynamic quality of the solvent with respect to micelles is slightly monotonically improved and the hydrodynamic sizes of micelles in 0.05 M NaCl are increased. At the same time, such properties as the weight-average degree of aggregation of macromolecules in a micelle, the dimensions of the corona in 0.05 M NaCl, and the dispersion stability of micelles in aqueous-saline solution abruptly change when the content of charged units in the lyophilizing block is 60-70 mol %. After addition of oppositely charged polyelectrolytes or low-molecular-mass surfactants into the micellar solution, poly-electrolyte complexes form and the solubility of these complexes in an excess oppositely charged component likewise changes abruptly with variation in the fraction of charged units in the range from 60 to 70 mol %. A qualitative description is advanced to explain the effect of linear charged density of the lyophilizing block on the self-assembly and complexing behavior of diblock copolymers in aqueous solutions.

AB - The effect of linear charge density of the ionogenic block on the self-assembly of the amphiphilic diblock copolymer based on polystyrene and poly(4-vinylpyridine) partially alkylated by ethyl bromide in aqueous solutions at pH 9 is studied by UV spectrophotometry and dynamic and static light scattering. During dispersion in water, the diblock copolymer forms micelles composed of the hydrophobic polystyrene core and the amphiphilic lyophilizing corona consisting of N-ethyl-4-vinylpyridinium bromide ionic units and uncharged units of 4-vinylpyridine. It is shown that with a change in the fraction of charged units in the lyophilizing block from 30 to 90 mol %, the thermodynamic quality of the solvent with respect to micelles is slightly monotonically improved and the hydrodynamic sizes of micelles in 0.05 M NaCl are increased. At the same time, such properties as the weight-average degree of aggregation of macromolecules in a micelle, the dimensions of the corona in 0.05 M NaCl, and the dispersion stability of micelles in aqueous-saline solution abruptly change when the content of charged units in the lyophilizing block is 60-70 mol %. After addition of oppositely charged polyelectrolytes or low-molecular-mass surfactants into the micellar solution, poly-electrolyte complexes form and the solubility of these complexes in an excess oppositely charged component likewise changes abruptly with variation in the fraction of charged units in the range from 60 to 70 mol %. A qualitative description is advanced to explain the effect of linear charged density of the lyophilizing block on the self-assembly and complexing behavior of diblock copolymers in aqueous solutions.

UR - http://www.scopus.com/inward/record.url?scp=77956457270&partnerID=8YFLogxK

U2 - 10.1134/S0965545X10060027

DO - 10.1134/S0965545X10060027

M3 - Article

AN - SCOPUS:77956457270

VL - 52

SP - 574

EP - 585

JO - Polymer Science - Series A

JF - Polymer Science - Series A

SN - 0965-545X

IS - 6

ER -