LIGHT-SCATTERING STUDY OF SALT-FREE POLYELECTROLYTE BEHAVIOR OF MONOTELECHELIC IONOMERS IN A POLAR-SOLVENT

Salt-free polyelectrolyte behaviour which is typically observed at low polymer concentrations for polyelectrolyte aqueous solutions and rand om ionomer non-aqueous solutions (in polar solvents) (i.e., negative a ngular dependence of the reciprocal scattering in static light scatter ing and an appearance of the fast mode in dynamic light scattering) ha s been observed for monotelechelic ionomer solutions in a polar solven t. This indicates that only single charge (per chain) is sufficient to produce intermolecular electrostatic interactions, which are responsi ble for such characteristic behaviour. However, the 'characteristic' b ehaviour, which is typically observed at higher concentrations for pol yelectrolyte and random ionomer solutions (i.e., large positive appare nt radius of gyration in static scattering and appearance of the slow mode in addition to the fast mode in dynamic scattering) has not been observed to date for monotelechelic ionomer solutions. The absence of high-concentration characteristics for the monotelechelic ionomer solu tions gives additional insight as to the nature and structure of 'hete rogeneities' in salt-free polyelectrolyte solutions, which is still co ntroversial. Copyright (C) 1996 Elsevier Science Ltd.