LASER-LIGHT SCATTERING STUDY OF A RIGID-ROD POLYELECTROLYTE

Static light scattering (SLS), dynamic light scattering (DLS), and dep olarized dynamic Light scattering (DDLS) were employed to study methan olic solutions of an intrinsically stiff rigid-rod polyelectrolyte con sisting of a poly(p-phenylene) backbone with dodecyl side chains. The solutions of the rigid rod polymers exhibit polyelectrolyte-solution p roperties at low counterion concentrations of tetramethylammonium chlo ride (TMACl). At higher salt concentrations, the single polymer molecu les and the aggregates coexist in solution. The amount of aggregates v aries with the polymer concentration and the nature of the counterions . By combining SLS with DLS studies, a new way of characterizing the b asic parameters (such as the weight average molecular weight and the r adius of gyration of the single polymer chains and the aggregation num ber of the aggregates) of the rodlike polyelectrolyte polymer chains i n the presence of the corresponding aggregates has been presented. DDL S studies allowed for elucidation of the aggregated structures.