Dissipative Particle Dynamics Study of the pH-Dependent Behavior of Poly(2-vinylpyridine)-block-poly(ethylene oxide) Diblock Copolymer in Aqueous Buffers

0427851 - ÚCHP 2015 RIV US eng J - Journal Article
Posel, Zbyšek - Limpouchová, Z. - Šindelka, K. - Lísal, Martin - Procházka, K.
Dissipative Particle Dynamics Study of the pH-Dependent Behavior of Poly(2-vinylpyridine)-block-poly(ethylene oxide) Diblock Copolymer in Aqueous Buffers.
Macromolecules. Roč. 47, č. 7 (2014), s. 2503-2514. ISSN 0024-9297. E-ISSN 1520-5835
R&D Projects: GA ČR GCP205/11/J043
Grant - others:GA ČR(CZ) GAP106/12/0143
Institutional support: RVO:67985858
Keywords : monte-carlo simulations * union-type micelles * block-copolymer
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 5.800, year: 2014

The paper describes the pH-dependent self-assembly of a diblock copolymer, poly(2-vinylpyridine)-block-poly(ethylene oxide), P2VP-PEO in aqueous media using computer simulations. We employed the dissipative particle dynamics (DPD) method and found that the copolymer with electrically neutral (i.e., deprotonated) or very low-protonated P2VP blocks form multimolecular spherical core shell micelles with insoluble P2VP cores in neutral and alkaline solutions, while protonization (ionization) of P2VP blocks exceeding 25% provokes the dissociation of micelles in single chains in acidic media. The finding that a clearly pronounced transition occurs in a restricted pH region slightly above pK(A)(ap) (where pK(A)(ap) is the apparent dissociation constant of the conjugated acid P2VPH(+)) is in good agreement with the experimental data (Macromolecules 1996, 29, 6071-6073). This suggests that (i) the tested model is reasonable and the mutual relationship between the parameters used in the soft repulsive and electrostatic potentials was set appropriately and (ii) the DPD method is a suitable simulation technique for studying phenomena accompanied by pronounced changes in the global properties of complex polymer and polyelectrolyte systems. Although we studied the behavior of only one specific system, the simulation yields a generic pattern for the pH-dependent self-assembly of copolymers containing one neutral water-soluble block and one annealed (weak) polyelectrolyte block with fairly hydrophobic backbone.
Permanent Link: http://hdl.handle.net/11104/0235273