(3co) Structure, Rheology and Dielectric Properties of Nanostructured Amphiphile/Ionic Liquid Mixtures

Wagner, N. J. - Presenter, University of Delaware

Room temperature ionic liquids (RTIL) have received a great deal of attention due to their remarkable properties including high thermal and chemical stability, negligible vapor pressure, high ionic conductivity and wide electrochemical window. Nanoscale self-assembly in RTIL extends the usefulness of these compounds by providing structure and viscoelasticity. During the last year I have begun a systematic exploration of self-assembly of amphiphilic compounds (including ionic surfactants and block copolymers) in ionic liquids.  I am particularly interested in the relation between the structure, the thermodynamics and the rheological and dielectric properties of amphiphile/ionic liquid systems. To study different aspects of these relationships, we use a number of experimental techniques, including SALS, SANS and flow-SANS, shear rheology, flow-birefringence and rheo-dielectrics measurements, optical polarizing microscopy and electronic microscopy as well as titration calorimetry. During the poster session I will present some of our most remarkable findings. For instance, we observed spontaneous formation of vesicles and formation of a very stable bicontinuous sponge phase in solutions of didodecyldimethylammonium bromide (DDAB) in ethylammonium nitrate (EAN), which are not observed in DDAB/water solutions. Another exciting finding is the formation of very long, entangled, viscoelastic and highly conductive wormlike micelles formed by a Pluronic triblock copolymer in EAN. Additionally, I am exploring two of the applications of these systems: (1) synthesis of highly ordered templated mesoporous silicates and (2) intra and inter-micelle photopolymerization of functionalized amphiphiles to generate nanostructured ruber-like materials.