Polysiloxane ionomers bearing pendant quaternary ammonium groups were synthesized through the Menshutkin reaction of poly(,gamma-chloropropylmethylsiloxane-co-dimethylsiloxane) with N,N-dimethylbenzylamine. Ion aggregation in the ionomers with different contents of the quaternary ammonium groups was investigated by torsion braid analysis, transmission electron microscopy, and rheological measurements. It was found that the incorporation of the quaternary ammonium groups did not make a significant effect on the glass transition temperature of the polysiloxane matrix. The glass transition of the cluster phase was found in the range of -20-40degreesC, depending on the concentration of the ion pair. The cluster phase was visualized under TEM when the concentration of the quaternary ammonium group exceeded a critical value. It was indicated by rheological data that the movement of polymer chains in the cluster phase of the polysiloxane ionomers was not restricted at the room temperature, which might be related to the weaker interaction between the bulky quaternary ammonium ion pairs.