title: Electrostatic binding of oppositely charged surfactants to spherical polyelectrolyte brushes.
abstract: We use Brownian dynamics (BD) simulations to investigate the formation and structural characteristics of the complex between a spherical polyelectrolyte brush (SPB) and oppositely charged surfactants. Increasing the amount of added surfactants leads to a collapsed conformation of the SPB and the number of adsorbed surfactants exhibits a linear dependence. Nevertheless, the surfactant uptake into the SPB does not increase with further addition of surfactants. It is found that the surfactant length has a strong influence on the SPB conformation and the adsorption properties of surfactant. Upon changing the surfactant length from 3 to 11, the SPB undergoes a swelling-deswelling-reswelling conformational transition. The brush deswelling is due to the increase in the surfactant uptake. The increasing size of adsorbed aggregates is a main reason for reswelling of the SPB. A non-linear relationship between the brush thickness and the grafting density is observed. Especially at intermediate grafting densities, increasing the number of grafted chains has a weak effect on the brush thickness. We also find that a completely collapsed brush conformation occurs at high surfactant/SPB charge ratios or large surfactant lengths, while the brush layer is in a partly collapsed or extended state at an intermediate charge ratio and surfactant length.
authors.affiliation: College of Mechanical Science and Engineering, Jilin University, Changchun, 130022, PR China. qqcao07@mails.jlu.edu.cn
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Cao
authors.forename: Chuncheng
authors.initials: C
authors.lastname: Zuo
authors.forename: Lujuan
authors.initials: L
authors.lastname: Li