Abstract

The micellization of several Pluronics (PEO-PPO-PEO triblock copolymers) was investigated by Differential Scanning Calorimetry (DSC). These copolymers were also characterized and purified by liquid chromatography. The PEO/PPO compositions of Pluronics were determined by 'H-NMR. The thermograms from DSC showed a pre micellization shoulder for L81 and L121 solutions. The effects of temperature, PO/EO ratios and impurities on the micellization of copolymers were investigated. The origin of the shoulders in DSC thermograms was shown to be due to the most hydrophobic components in the copolymers, which could be removed by hexane extraction. Low molecular weight fractions of the copolymers were separated by interaction chromatography. The low molecular weight fractions did not contribute to the micellization of the copolymers.