Giant permittivity and dynamic mobility observed for spherical polyelectrolyte brushes

Abstract

We present a study of the electrodynamic behavior of concentrated suspensions of spherical polyelectrolyte brushes (SPBs). The dynamic mobility of the SPBs exhibits giant values. Concomitantly, the dielectric spectra of suspensions of these particles display enormous loss peaks in the kHz frequency range. The strong dielectric relaxation is a direct consequence of the inhomogeneity of the counterion distribution inside the polyelectrolyte layer. As can be concluded from the experimentally determined relaxation frequency, the mobility of monovalent counterions is strongly diminished in the brush region. The dynamic behavior of the SPBs at high volume fractions can be explained by the assumption that the polyelectrolyte chains deform when particles approach each other.