Effect of Polymeric Organic Additives

Higher-molecular-weight glycols are believed to form true polymer-surfactant complexes in which the glycol is in the form of a random coil bound to the surfactant with its hydrophilic groups oriented toward the aqueous phase. Here the dye is solubilized in the POE-rich region (Tokiwa, 1973b). 

The relation between the extent of solubilization and the structures of solubi-lizate and surfactant-polymer complex is not completely clear. Aromatic hydrocarbons appear to be more highly solubilized than aliphatic hydrocarbons by complexes of anionic surfactants and hydrophilic polymers with no proton-donating groups, such as polyvinylpyrrolidone, but the nature of the forces involved is not clear. Some cationic surfactant-polymer complexes are broken by the solubilization of aromatic hydrocarbons. It has been suggested that structural compatibility between solubilizate and polymer may be a factor and that the function of the surfactant is to increase the hydrophilic character of the polymer and to promote contact between polymer and solubilizate (Saito, 1967). 

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