Scaling Laws of Polyelectrolyte Adsorption
Abstract
Adsorption of charged polymers (polyelectrolytes) from a semi-dilute solution to a charged surface is investigated theoretically. We obtain simple scaling laws for (i) the amount of polymer adsorbed to the surface, Gamma, and (ii) the width of the adsorbed layer D, as function of the fractional charge per monomer p and the salt concentration c_b. For strongly charged polyelectrolytes (p<1) in a low-salt solution, both Gamma and D scale as p^{-1/2}. In salt-rich solutions D~c_b^{1/2}/p whereas the scaling behavior of Gamma depends on the strength of the polymer charge. For weak polyelectrolytes (p<<1) we find that Gamma~p/c_b^{1/2} while for strong polyelectrolytes Gamma~c_b^{1/2}/p. Our results are in good agreement with adsorption experiments and with numerical solutions of mean-field equations.
Cite
@article{arxiv.cond-mat/9706090,
title = {Scaling Laws of Polyelectrolyte Adsorption},
author = {I. Borukhov and D. Andelman and H. Orland},
journal= {arXiv preprint arXiv:cond-mat/9706090},
year = {2009}
}
Comments
13 pages, RevTex + epsf, 9 postscript figures; minor corrections