Hydrodynamic, dynamooptical, and electrooptical properties of the ionomer - sulfonated polystyrene containing 1.35 mol % of sodium sulfonate groups - were studied in m-xylene. In contrast to polystyrene, the sedimentation coefficient of the ionomer increases with an increase in the polymer concentration in solution. The concentration dependences of the reduced viscosity, translational diffusion coefficient, and sedimentation coefficient of the ionomer can be described by the "open" association model. The electric birefringence of the ionomer solutions is caused by the orientation of asymmetric multiplets of ionic groups.