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Molecular dynamics studies of anchored polyelectrolytes
Author(s) -
Csajka Félix S.,
van Der Linden Catharina C.,
Seidel Christian
Publication year - 1999
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19991460133
Subject(s) - polyelectrolyte , counterion , counterion condensation , chemical physics , brush , diffusion , condensation , anisotropy , molecular dynamics , coulomb , chemistry , ion , materials science , polymer chemistry , thermodynamics , polymer , physics , computational chemistry , quantum mechanics , organic chemistry , electron , composite material
We study polyelectrolytes end‐grafted to a surface in a model which includes counterions explicitly and treats the full long‐range Coulomb interaction. For strongly charged polyelectrolytes the counterions are localized inside the brush and electroneutrality is satisfied locally. Under these conditions, we find that the brush thickness is linearly proportional to the chain length and the grafting density. The counterion distribution is strongly inhomogeneous, and counterion condensation can be observed although the Bjerrum length is smaller than the average bond length. Varying the Bjerrum length we find a non‐monotonic behaviour of the brush height. Counterion diffusion is anisotropic, and is enhanced at higher grafting densities. For partially charged polyelectrolytes we obtain a crossover from quasi‐neutral behaviour to the strongly charged behaviour reported above.