Insight into the structure of oppositely charged surfactant–polymer system by dielectric spectroscopy

Abstract

The interaction between polymer (poly(acrylic acid)) and surfactant 12-2-12 (ethanediyl-1,2-bis(dimethyldodecylammonium bromide)) in aqueous solution was investigated by dielectric relaxation spectroscopy (DRS) over a frequency range from 40 Hz to 110 MHz. To better understand the interaction, the dielectric behaviors of surfactant 12-2-12 solution and PAA solution were also separately studied. For surfactant 12-2-12 solution, one dielectric relaxation was observed above the critical micellar concentration, which was attributed to the interface polarization. For polymer PAA solution, two dielectric relaxation processes were evident which were ascribed to the counterion fluctuation along the whole chain and within the scale of correlation length of PAA polymer respectively. For the mixture of PAA and surfactant 12-2-12 solution, the dielectric behavior was discussed through comparing it with that of PAA and surfactant 12-2-12 solution. The possible interaction pattern and the structure of surfactant 12-2-12/PAA complex were proposed on the basis of the dielectric behavior.