Studies of the Interaction of Cationic Gemini Surfactants with Polymers and Triblock Copolymers in Aqueous Solution

Abstract

The physical interactions occurring between members of the N,N′-bis (dimethyldodecyl)-α,ω-alkanediammonium dibromide (m–s–m, m=12, s=3 and 6) series of gemini surfactants and the neutral polymers polyethylene oxide (PEO) and polypropylene oxide (PPO), and triblock copolymers of polyethylene oxide–polypropylene oxide–polyethylene oxide (PEO–PPO–PEO), have been investigated in aqueous solution using specific conductance, fluorescence intensity, density, and equilibrium dialysis techniques. For the conditions investigated, the interactions were found to be markedly different from those generally observed in surfactant–polymer systems, with an absence of the typically observed critical concentrations. Instead, it is observed that increased surfactant concentration in the polymer coil regions results in a gradual change from clusters of monomer surfactant bound to the polymer to the formation of regular micelles.