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[摘要]：The solvent-induced association and micellization processes of amphiphilic rod-coil diblock copolymers, poly(ethylene oxide)-b-poly{(+)-2,5-bis[4'-((S)-2-methylbutoxy)phenyl]styrene} (PEO104-b-PMBPSn, with n being 17, 30, 45, 53, and 106, respectively), were studied in situ by laser light scattering. In dioxane, a selective solvent for PMBPS block, the copolymer preserved the single-chain conformation. With the addition of water, a selective solvent for PEO block, the block copolymer underwent two difference processes: the association governed by PEO and the micellization governed by PMBPS. Because PMBPS would be dominant at elevated water content, three occurrences, the formation of associate, the formation of micelles, and the breakdown of associate, were observed in sequence with increasing water content. However, under the conditions where the rate of disassociation was much slower than that of micellization, the structure of the associate was "frozen" by the rod blocks, and mixed structures of associate and micelle were obtained. The associate formed at elevated water content was controlled by kinetics. Its formation was mainly determined by the PEO/PM BPS block ratio and the water addition rate. |
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