Microscopic Insights into Ion Gel Dynamics using Neutron Spectroscopy

Published

August 1, 2012

Author(s)

Maiko Kofu, Takenori Someya, Soichi Tatsumi, Kazuhide Ueno, Takeshi Ueki, Masayoshi Watanabe, Takuro Matsunaga, Mitsuhiro Shibayama, Victoria Garcia Sakai, Madhu Sudan Tyagi, Osamu Yamamuro

Abstract

We have investigated the microscopic dynamics of ion gels consisting of a PMMA [poly(methyl methacrylate)] network and EMITSFI [1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide] as the ionic liquid, by means of quasi-elastic neutron scattering (QENS). These ion gels interestingly exhibit two glass transitions (T_gS) which drastically decrease as the ionic liquid content increases. QENS allows us to probe the dynamics of PMMA and the EMI cation separately, by selectively deuterating the individual components, and gain insight into the glassy properties of this system. A comprehensive analysis of the QENS spectra was performed, revealing a number of characteristic relaxtions, including intramolecular ones, each of which was assigned. We found that the activation energy from PMMA diffusion decreases with increasing in ionic liquid content, corresponding to a plasticization of the polymer. The ionic liquid showed two characteristic relaxations: a motion strongly coupled to a higher effective T_g, and an ionic diffusion associated with ionic liquid molecules far from the polymer chains which behave nearly as free liquid, exhibiting a lower T_g.

Citation

Soft Matter

Volume

8

Pub Type

Journals

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Keywords

ionic gels, dynamics, neutron scattering

Citation

Kofu, M. , Someya, T. , Tatsumi, S. , Ueno, K. , Ueki, T. , Watanabe, M. , Matsunaga, T. , Shibayama, M. , Garcia Sakai, V. , Tyagi, M. and Yamamuro, O. (2012), Microscopic Insights into Ion Gel Dynamics using Neutron Spectroscopy, Soft Matter, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=910840 (Accessed July 17, 2024)