title: Nanocomposite ion gels based on silica nanoparticles and an ionic liquid: ionic transport, viscoelastic properties, and microstructure.
abstract: The dispersion of silica nanoparticles made an ionic liquid, 1-ethyl-3-methyl imidazolium bis(trifluoromethanesulfonyl)amide ([C(2)mim][NTf(2)]), gelled even by the addition of 2-3 wt %, due to the formation of interconnected particulate silica networks in [C(2)mim][NTf(2)]. The ionic transport and viscoelastic properties of these nanocomposite ion gels were investigated in relation to the microstructure. Despite their solid-like behavior, the nanocomposite ion gels exhibited a high ionic conductivity of approximately 10(-2) S cm(-1) at 30 degrees C, which is comparable to that of neat [C(2)mim][NTf(2)]. Intriguing viscoelastic responses, such as shear-thinning and shear-induced sol-gel transitions, were found in all of the nanocomposite ion gels. By adjusting the silica concentration, the elastic modulus ( G') could be precisely controlled in a range of more than 3 orders of magnitude and reached approximately 10(6) Pa without a considerable decrease in the ionic conductivity; the characteristic viscoelastic response was also maintained. For the aggregation mechanism in [C 2 mim][NTf(2)], the reaction-limited cluster aggregation (RLCA) model was proposed by rheology and light scattering measurements.
authors.affiliation: Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan .
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Ueno
authors.forename: Kenji
authors.initials: K
authors.lastname: Hata
authors.forename: Toru
authors.initials: T
authors.lastname: Katakabe
authors.forename: Masashi
authors.initials: M
authors.lastname: Kondoh
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Watanabe