Interaction of monomeric normal L44 [(PEO)(10)(PPO)(23)(PEO)(10)]) and reverse 10R5 [(PPO)(8)(PEO)(22)(PPO)(8)] pluronics designated as L and R, respectively, and their mixtures with the anionic surfactant sodium N-dodecanoylsarcosinate (SDDS) in aqueous medium has been studied by tensiometry, conductometry, calorimetry and dynamic light scattering methods. The critical aggregation concentration (CAC), concentration of maximum binding (C-s), and the extended critical micelle concentration (CMCe) of SODS resulted from the interaction have been presented. L has shown the formation of CAC, C-s and CMCe, whereas R has shown the absence of CAC but the presence of both C-s and CMCe. Micellization of SDDS is an endothermic process whereas the formation of CAC and CMCe is exothermic events, the formation of C-s is endothermic. The hydrodynamic diameter (D-h) and zeta potential of L and R, and their SDDS interacted species have been determined. D-h decreased with increasing SDDS concentration for L whereas it was invariant for R. Mixed L and R in varied proportions have been also examined in the solution state to probe into their mutual interaction, and interaction with SDDS. The formation of CAC of their mixtures was absent; CMCe formation was exothermic while that of C-s was endothermic like their individuals. (C) 2013 Elsevier Inc. All rights reserved.