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Comparative Thermodynamic Studies of the Micellization of Amphiphilic Block Copolymers before and after Cyclization
| Title: | Comparative Thermodynamic Studies of the Micellization of Amphiphilic Block Copolymers before and after Cyclization |
| Authors: | Yamamoto, Takuya Browse this author →KAKEN DB | | Masuda, Yuki Browse this author | | Tezuka, Yasuyuki Browse this author | | Korchagina, Evgeniya Browse this author | | Winnik, Francoise M. Browse this author |
| Keywords: | Copolymers | | Hydrophobicity | | Micelles | | Micellization | | Polymers |
| Issue Date: | 5-Jan-2023 |
| Publisher: | American Chemical Society |
| Journal Title: | Langmuir |
| Volume: | 38 |
| Issue: | 17 |
| Start Page: | 5033 |
| End Page: | 5039 |
| Publisher DOI: | 10.1021/acs.langmuir.0c03358 |
| Abstract: | The enthalpy and entropy of micellization in water, AHmic and ASmic, respectively, of three linear amphiphilic BAB block copolymers consisting of either poly(methyl acrylate) (Mn similar to 1200 and 700 Da) or poly(ethyl acrylate) (Mn similar to 800 Da) as hydrophobic (B) segments and poly(ethylene oxide) (PEO) as the hydrophilic (A, Mn similar to 3000 Da) segment were determined by isothermal titration calorimetry (ITC). The AHmic and ASmic of the cyclic AB block copolymers obtained by cyclization of the linear triblock copolymers were determined under the same conditions. The AHmic value of the cyclic copolymers was smaller than that of their linear precursors. The ASmic value showed the same trend, but the relative difference between the cyclized and linear copolymers was less pronounced. The hydrodynamic diameter (Dh), critical micelle concentration (CMC), molecular weight (Mw-mic), and second virial coefficient (A2) of the micelles were determined. The Dh value of the cyclic copolymer micelles was smaller than the linear counterpart. On the other hand, the CMC value became larger, whereas the A2 value was comparable or increased by cyclization. Overall, the results suggest that, in the unimer state, the hydrophobic segments of the cyclized copolymers form a tightly coiled structure to minimize contact with water, resulting in the smaller AHmic value. Contrary to the linear copolymer micelles, the cyclic copolymer micelles have no "dangling chains", which may explain the topology-driven slight difference in the ASmic value. |
| Rights: | This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/articlesonrequest/AOR-QIAIGG6V6KATDBVSNQJG. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/87595 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 山本 拓矢
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