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Regular and irregular micelles formed by A LEL triblock copolymer in aqueous solution |
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| Authors: | Tianbo Liu Kwangsok Kim Benjamin S Hsiao |
| Affiliation: | a Department of Physics, Brookhaven National Laboratory, Upton, NY 11973-5000, USA b Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA c Department of Materials Sciences and Engineering, State University of New York at Stony Brook, Stony Brook, NY 11794-2275, USA |
| Abstract: | Laser light scattering (LLS) techniques were used to characterize the micellization of poly(d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (LEL) triblock copolymer (MW 1K-2K-1K) in aqueous solution. We observed the existence of both thermodynamically stable flower-like micelles (regular micelles) and large, less soluble nanoparticles (irregular micelles) in dilute aqueous solutions with the same preparation procedure. Both kinds of micelles were found to co-exist with single copolymer chains. The initial copolymer concentration determines the nature of the micelles. The regular core-shell micelle formation follows a closed association mechanism, resulting in flower-like micelles. The hydrophobicity of a L unit is estimated as ∼0.5-0.6 B (polyoxybutylene) units from the micellization parameters, which is quite consistent with earlier estimations obtained from EL diblock copolymers. |
| Keywords: | Light scattering Micelles Block copolymer |
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