Dielectric properties of a model cationic ionomer

An alpha,omega-bis(dimethylamino)polyisoprene (M(n)BAR = 5000) has been quaternized by alpha,alpha'-dibromo-p-xylene with formation of a model cationic ionomer. Dielectric spectroscopy has shown an alpha-relaxation which corresponds to the micro-Brownian motion of chain segments directly attached to the quaternary ammonium dipoles. A shoulder on the low-temperature side of the alpha-relaxation has been assigned to the contribution of the polymer segments, the mobility of which is not restricted by the multiplets. That situation is in full agreement with the multiplet-cluster concept recently revisited by Eisenberg et al.