Electric field orientation of sonicated κ-carrageenan in aqueous solution: ionic polarization of loosely bound counterions

Abstract

The electric field orientation of κ-carrageenan in aqueous solution was investigated by the reversing-pulse electric birefringence method at 633 nm and 33°C. The observed field orientation was attributed to the fast-induced polarization of the counterions (K + ions) in the ionized polymer domain. Since the charge density parameter ξ of non-helical and elongated κ-carrageenan is 0.66, the fast-induced ionic polarization is probably due to the counterions loosely bound by Debye-Hückel type electrostatic forces, but not due to the condensed counterions.