Surfactant characteristics of random block polyelectrolyte polyester emulsifier (SMTAPE) in aqueous solution and on polystyrene latex particles

The surfactant characteristics of novel random block polyelectrolyte polyes ter emulsifiers, SMTAPE, were investigated by analyzing the surface tension of a variety of SMTAPE with different molecular weights and different hydr ophilicities in aqueous solution, and also by studying the change of surfac e tension of polystyrene (PS) latex with increasing SMTAPE emulsifier conce ntration. The SMTAPE emulsifier was found to lower the surface tension of w ater by about 15 mN/m at the CMC. All of the investigated SMTAPE emulsifier s show two CMC break points, which were attributed to their broad molecular weight distribution. A Langmuir type adsorption isotherm was observed in t his system. The surface area occupied by an SMTAPE molecule on a PS latex p article at 25 degrees C was found to be 187 Angstrom(2) at saturation. The conformation of SMATAPE emulsifier molecule adsorbed on a PS latex particle is thought to be a hydrophobic segment "trains" anchored to the polymer su rface. (C) 2000 Elsevier Science Ltd. All rights reserved.