Efficient Synthesis of Asymmetric Miktoarm Star Polymers

Journal Article · Wed Jan 08 00:00:00 EST 2020 · Macromolecules

DOI:https://doi.org/10.1021/acs.macromol.9b02380· OSTI ID:1594104

Levi, Adam E. ^[1]; Fu, Liangbing ^[2]; Lequieu, Joshua  ^[3]; Horne, Jacob D. ^[4]; Blankenship, Jacob ^[1]; Mukherjee, Sanjoy  ^[3]; Zhang, Tianqi ^[2]; Fredrickson, Glenn H.  ^[5]; Gutekunst, Will R.  ^[2]; Bates, Christopher M.  ^[6]

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1. Univ. of California, Santa Barbara, CA (United States). Dept. of Chemistry and Biochemistry
2. Georgia Inst. of Technology, Atlanta, GA (United States). School of Chemistry and Biochemistry
3. Univ. of California, Santa Barbara, CA (United States). Materials Research Lab.
4. Univ. of California, Santa Barbara, CA (United States). Dept. of Chemical Engineering
5. Univ. of California, Santa Barbara, CA (United States). Materials Research Lab.; Univ. of California, Santa Barbara, CA (United States). Dept. of Chemical Engineering; Univ. of California, Santa Barbara, CA (United States). Dept. of Materials
6. Univ. of California, Santa Barbara, CA (United States). Dept. of Chemistry and Biochemistry; Univ. of California, Santa Barbara, CA (United States). Dept. of Chemical Engineering

Asymmetric miktoarm star polymers produce unique material properties, yet existing synthetic strategies are beleaguered by complicated reaction schemes restricted in both the monomer scope and yield. In this work, we introduce a new synthetic approach coined “μSTAR”, miktoarm synthesis by termination after ring-opening metathesis polymerization, that circumvents these traditional synthetic limitations by constructing the block–block junction in a scalable one-pot process involving (1) grafting-through polymerization of a macromonomer followed by (2) in situ enyne-mediated termination to install a single mikto-arm with exceptional efficiency. This modular μSTAR platform cleanly generates AB_n and A(BA')_n miktoarm star polymers with unprecedented versatility in the selection of A and B chemistries as demonstrated using many common polymer building blocks. The average number of B or BA' arms (n) is easily controlled by the equivalents of Grubbs catalyst. Although these materials are characterized by dispersity in n that arises from the statistics of polymerization, they self-assemble into mesophases that are identical to those predicted for precise miktoarm stars. In summary, the μSTAR technique provides a significant boost in design flexibility and synthetic simplicity while retaining the salient phase behavior of precise miktoarm star materials.

• Research Organization: Univ. of California, Santa Barbara, CA (United States); Stanford Univ., CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
• Grant/Contract Number: SC0019001; AC02-76SF00515; AC02-05CH11231; DMR-1720256; CNS-1725797
• OSTI ID: 1594104
• Journal Information: Macromolecules, Vol. 53, Issue 2; ISSN 0024-9297
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
miktoarm star
asymmetric star
polymer architecture
macromonomer
grafting-through polymerization
ring-opening metathesis polymerization
ROMP