Effect of head/tail groups on molecular induced aggregation of polycationic cyclodextrin towards anionic surfactants

The molecular induced aggregation behaviors of a polycationic cyclodextrin, i.e. per-6-deoxy-6-(1-methylimidazol-3-ium-3-yl)-β-cyclodextrin ( 1 ), towards five anionic surfactants, i.e. sodium decyl sulfonate (SDES), sodium undecyl sulfonate (SUS), sodium dodecyl sulfate (SDS), sodium lauryl sulfate (SLS) and sodium dodecyl benzene sulfonate (SDBS), were comprehensively investigated in aqueous solution. The results showed that the introduction of 1 could efficiently decrease the critical aggregation concentrations (CAC) of the selected surfactants by a factor of 14-467, leading to the formation of nanoscale spherical particles with a diameter of 200-400 nm and nearly neutral or moderate positive zeta potential. Significantly, the resultant 1 /SLS and 1 /SDBS aggregates exhibited the ability of loading both anionic and neutral model substrates. A polycationic cyclodextrin significantly decreased the critical aggregation concentrations of anionic surfactants with different head/tail groups by a factor of 14-467 through the molecular induced aggregation.