Hierarchical Sol-Gel Transition Induced by Thermosensitive Self-Assembly of an ABC Triblock Polymer in an Ionic Liquid

Yuzo Kitazawa, Takeshi Ueki, Lucas D. McIntosh, Saki Tamura, Kazuyuki Niitsuma, Satoru Imaizumi, Timothy P. Lodge, Masayoshi Watanabe

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41 Scopus citations


We investigated a hierarchical morphology change and accompanying sol-gel transition using a doubly thermosensitive ABC-triblock copolymer in an ionic liquid (IL). The triblock copolymer contains two different lower critical solution temperature (LCST) thermosensitive polymers, poly(benzyl methacrylate) (PBnMA) and poly(2-phenylethyl methacrylate) (PPhEtMA), as the end blocks and poly(methyl methacrylate) (PMMA) as the middle block (PBnMA-b-PMMA-b-PPhEtMA: BMP). BMP undergoes a hierarchical phase transition corresponding to the self-assembly of each of the thermosensitive blocks in the IL, and a sol-gel transition was observed in concentrated, above 10 wt %, polymer solutions. The gelation behavior was affected by polymer concentration, and at 20 wt %, the BMP/IL composite showed a phase transition, with increasing temperature, from solution through a jammed micelle suspension to a physically cross-linked gel. Each phase was formed reversibly and rapidly over the corresponding temperature range. The jammed micelle and cross-linked gel states were characterized using viscoelastic measurements and small-angle X-ray scattering (SAXS).

Original languageEnglish (US)
Pages (from-to)1414-1423
Number of pages10
Issue number4
StatePublished - Mar 8 2016

Bibliographical note

Funding Information:
This work was financially supported by the Grants-in-Aid for Scientific Research of #A-23245046 (M.W.), 15H05495 and 26620164 (T.U.), the National Science Foundation Polymers Program through Award DMR-1206459 (T.P.L.), and in part from the Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists (No. 13J00192 to Y.K.). SAXS measurements were performed at the DuPont - Northwestern - Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by E.I. DuPont de Nemours & Co., The Dow Chemical Company, and Northwestern University. Use of the APS, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract DE-AC02-06CH11357.

Publisher Copyright:
© 2016 American Chemical Society.


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