Surfactant-induced lyotropic behavior of flexible polymer solutions

A theoretical analysis is presented to describe the stiffening of flexible, linear polymer chains due to complexation with oligomeric surfactants. These surfactants might be functionalized protonic acids or possess other types of end groups that exhibit strong, specific interactions with the flexible polymer backbone. The enhancement of the persistence length due to steric interactions between the bound surfactant tails is considered and the possibility of lyotropic behavior at finite polymer concentration is investigated. The results are discussed in the context of recent experiments by Cao and Smith, who reported liquid crystallinity in solutions of polyaniline complexed with camphorsulfonic acid