The behavior of surfactant aggregates in solutions was investigated by an ESR spin probe method. The following informations were obtained from analysis of spectra.
1) Two types of micelles were directly observed in commercially available sodium alkyl poly (oxyethylene) ether sulfate-alkyl poly (oxyethylene) ether mixed surfactant solutions.
2) Sodium dodecyl sulfate molecules (2 mM) incorporated into phospholipid bilayers (13.6 mM) formed clusters by themselves, causing phase separation of the bilayers.
3) Sodium 3- dodecyloxypoly (oxyethylene) -1-propane sulfonates interacted with an ESR spin probe even below the cmc. This was explained by the formation of ESR spin probe-induced micelles.
4) Butyl poly (oxypropylene) ether derivatives having polar dissociative functional groups on their terminal hydroxyl groups behaved in a manner similar to a reversed micelle or a W/O microemulsion system and were inverted to an O/W type through a transparent and viscoelastic gel stage with increasing a water content.