Dominant factors on the micellization of BnEmBn-Type triblock copolymers in aqueous solution

The micellization parameters of a series of oxyethylene/oxybutylene (BnEmBn) triblock copolymers (B4E40B4, B5E39B5, B5E91B5, B6E46B6, B7E22B7, B7E40B7, B10E271B10, and B12E260B12) were summarized to obtain collective conclusions on the dominant factors that affect the micellization of such sort of triblock copolymers in aqueous solution. The effects of the block lengths of both the hydrophobic end B blocks and the hydrophilic middle E block on the critical micellar concentrations, the association numbers, the second virial coefficients of micelles, the enthalpy of micellization, the hydrodynamic radius, and the intermicellar cross-linking are discussed. It was found that the micellization was mainly determined by the B block length while the micellar size and the intermicellar structure were influenced greatly by the E block length. The scaling theory that was derived from diblock copolymer micelle models can also be used in triblock copolymer miceller systems.