8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Wed 711:10-14:00P5.77Structure formation of Janus particlesYasutaka Iwashita, 1 Tomohiro Noguchi, 1 Taishi Kunisaki, 1 and Yasuyuki Kimura 11 Kyushu University, 6-10-1 Hakozaki, Higashi-ku, 8128581, Fukuoka, JapanJanus colloidal particles are colloid composed of two surfaces of different properties such ascharge, dielectricity and hydrophobicity. They have attracted much attention these years due totheir interesting behaviors; self-propelling by anisotropic surface catalysis, unique motion underexternal field, self-organization and so on. In this study we prepared mainly amphiphilic Janus colloidbased on the method of Jiang et al. [1] and focused on their aggregated structure formation inliquids. First, we dispersed our Janus colloid in ethanol-dodecane mixture with[4] tiny amount ofwater: Around room temperature the liquid phase-separates into polar and nonpolar phases. Afterphase separation, the particles attached to the polar-nonpolar interface and two-dimensional micellaraggergates, or colloidsomes were formed finally in the almost two-dimensional cell. On thefollowing shrinkage of the inner phase toward one-phase region, the aggregates showed bucklingdeformation as observed in vesicles or other colloidsomes. We also studied their aggregated structureformation in 2, 6-lutidine - water mixture: At the phase separation into water- and lutidinerichphase, which are polar and nonpolar phase respectively, the particles attached to the emergingdroplet and formed spherical micellar aggregates in a thick cell. These aggregates were oil-inwateror water-in-oil type depending on the composition of the lutidine-water mixture. In addition,depending on the number of the particles attached to a droplet, clusters of several different structureswere formed after the droplets disappeared in the one-phase region. Details of the aggregateswill be presented together with other results.[1] S. Jiang and S. Granick, Langmuir 24, p. 2438 (2008)77