INCLUSION COMPLEXES OF SOME NONIONIC SURFACTANTS WITH CYCLOMALTOOLIGOSACCHARIDES

The formation of inclusion complexes of some nonylphenyl and tributylphenyl poly(oxyethylene) surfactants [tensides, R-O-(CH2CH2O)(n)H] with cyclomalto-hexaose, -heptaose, and -octaose (cyclodextrins, CDs), and di- and tri-O-methylcyclomaltoheptaose was studied on the basis of changes in surface tension. The relative strength of the interaction of CD and tenside was measured by reverse-phase t.l.c. The CDs increased the surface tension of the more hydrophobic tensides and decreased that of the more hydrophilic tensides. The bulk of the hydrophobic moiety of tensides, the length of the poly(oxyethylene) chain, the CD-tenside molar ratio, and the salt concentration influenced significantly the surface tension. The strengths of the inclusion complexes were influenced significantly by the concentration of the CD, the diameter of the cavity, and the length of the poly(oxyethylene) chain. The formation of inclusion complexes may influence the performance of formulations containing tensides and a CD.