Block copolymer micelle formation in a solvent good for all the blocks

Autor: Bamin Khomami, Hanieh Niroomand, Sheng Hu, Xianggui Ye
Rok vydání: 2015
Předmět:
Zdroj: Colloid and Polymer Science. 293:2799-2805
ISSN: 1435-1536
0303-402X
Popis: To produce desired aggregate structures of copoly- mers, the copolymer is usually first dissolved in a common solvent that dissolves all the blocks. However, a solvent hav- ingtheexact samesolubilitytoalltheblocksofacopolymeris rare. Hence, it is extremely important to know whether the block copolymer forms micelle in a common solvent, and if it does, to know the micelle's structure. In this study, we used polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) dissolved in dimethyl formamide (DMF) as a model system to address block copolymer micelle formation and its structure in a solvent good for all the blocks as DMF dissolves both PS and P4VP. Our atomic force microscopy (AFM) and cryogenic-transmission electron microscopy (cryo-TEM) results clearly demonstrated that PS-b-P4VP with a wide range of molecular weight and P4VP composition in DMF forms a spherical micelle. Furthermore, contact angle measurements and TEM results clearly show that the micelle has a PS core and a P4VP corona. In com- paring the dry micelle and the micelle in DMF, we discovered that the micelle core is significantly swelled by DMF. Our findings suggest that soft-core micelles widely exist for block copolymers in solvents good for all the blocks but with significant selectivity between different blocks.
Databáze: OpenAIRE
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