講師：Jure Dobnikar (Department of Chemistry, University of Cambridge and Jozef Stefan Institute, Ljubljana, Slovenia)
題目：Field-induced self-assembly of suspended colloidal membranes
Superparamagnetic colloids in external time-dependent magnetic fields are a verstile tool to study the self-assembly process. We report experiments that probe self-assembly of micrometer-size colloids in both, in 2D confinement and in bulk systems. In quasi 2D confinement, the colloids interact via core-softened repulsive potentials and - in the absence of any attractive forces - clustering is observed and characterized. In 3D bulk systems, in a magic- angle precessing magnetic field, superparamagnetic spheres experience isotropic pair attraction similar to the van der Waals force between atoms. However, the complex many-body polarization interactions among them steer an ordered aggregation pathway consisting of growth of short chains, cross-linking and network formation, network coarsening, and consolidation of membrane patches ? resulting in one-particle-thick, robust, and self-healing membranes. We theoretically explain the membrane stability, their elastic and self-healing properties and the observed aggregation pathway. This generic scenario can be induced in any particles of large enough susceptibility.
講師：Paddy Royall ((Bristrol University, UK)
題目：Colloidal and metallic liquids out of equilibrium : linking structure and kinetics
The liquid state is central to two great challenges of condensed matter : crystallisation and dynamical arrest. We will consider the role of local structure in both. Due to the simplicity in their interactions, colloidal model systems form an ideal complement to computer simulation in tackling these problems. However, in crystallisation, the only system for which quantitative data exists, colloidal "hard" spheres, experiment and simulation disagree wildly. Meanwhile in dynamical arrest, the role of structure is highly controversial.
We shall use a novel structural analysis to tackle both crystallisation and dynamical arrest. With a careful comparison between experiment and simulation, we find evidence to support the discrepancy in nucleation rates, and reveal new pathways in crystallisation. Applying our methods to dynamical arrest, we find a clear structural mechanism for gelation. For the glass transition, we find clear structural changes which reveal a fundamental difference between these two modes of dynamical arrest : gelation is (quasi) first-order and vitrification is continuous.
講師：Francesca Serra （イタリア ミラノ大学 9/7-12/6まで相転移に滞在）
題目：Memory from topology: an experimental point of view
While the aim of conventional display technology based on nematic liquid
crystals (NLC) is to obtain a wholly aligned and defect-free material, new
technologies are starting to exploit the potential of topological defects,
i.e. regions where the NLCs are not aligned. Topological defects, in fact,
are responsible for the memory effects observed in liquid crystals confined
in bicontinuous porous materials. Moreover, the new discovery that the
geometry of the bicontinuous material affects the memory properties paves
the way to new types of bistable displays. Microfabrication techniques,
such as femtosecond laser ablation (FLICE) and two-photon polymerization,
allow the experimental observation of the topological defects in complex
and controlled geometry and also the experimental testing of the memory
properties under various conditions. In particular, two photon
polymerization allowed the fabrication of the first prototype of bistable
display based on the memory-from-topology principle.
講師：波多野 恭弘氏 (東京大学 地震研究所)
題目：Granular friction in a wide range of shear rates
The rheological properties of granular matter are important for analyzing various phenomena in geosciences, such as landslides, debris flows, and crater formation. Among the rheological properties of granular matter, the shear-rate dependence of the friction coefficient determines the stability of deformation and therefore has been paid major attention. Here we report simulation and experiment that address this problem. We conduct an experiment on the frictional properties of granular matter over a wide range of shear rate that covers both the quasistatic and the inertial regimes. We show that the friction coefficient exhibits negative shear-rate dependence in the quasistatic regime, whereas the shear-rate dependence is positive in the inertial regime. The crossover shear rate is determined in terms of the competition between two physical processes, namely frictional healing and anelasticity. We also find that the result does not depend on the shape of the grains and that the behavior in the inertial regime is quantitatively the same as that in some numerical simulations.
講師：Nasser Mohieddin Abukhdeir (Japan Society for the Promotion of Science Visiting Fellow*
National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba, Ibaraki Prefecture, Japan)
題目：Formation and Dynamics of Smectic-A Liquid Crystals
Over the past several decades many disruptive technological advancements have been enabled through
applications of liquid crystals. The majority of these applications utilize nematic liquid crystals (NLCs),
which have some degree of orientational order. Continuing this technological trend requires an
increased understanding of LC properties and, ideally, the ability to predict and control them to
achieve desired device function. In our work, simulation-based approaches are pursued to enable new
classes of LC devices. High-order smectic liquid crystals (SLCs), which exhibit translational in
addition to orientational order, are targeted in that they present additional challenges compared to
Simulations of the isotropic/smectic-A transition using a high-order phenomenological Landau-de
Gennes (LdG) model  will be presented. This model includes energetic couplings of nematic and
smectic order; both bulk order and coupling of the nematic director and smectic wave vector.
Simulation results show consistent agreement with experimental observations while providing new
insights into nanoscale SLC phenomena. Simulations capture the formation and dynamics of “giant”
dislocations  and the delicate balance between orientational and translational order in the vicinity
Finally, simulation results of SLC domains in shallow undercooling conditions are shown using a
non-isothermal extension to the LdG model . This extended model correctly predicts
diffusion-limited growth kinetics and novel nonmonotonic growth kinetics in regimes where
orientational (nematic) pre-ordering present .
 Mukherjee, P. K.; Pleiner, H. & Brand, H. R. Simple Landau model of the smectic-A-isotropic phase transition. Eur.
Phys. J. E, 2001, 4, 293-297.
 Abukhdeir, N. M. & Rey, A. D. Defect kinetics and dynamics of pattern coarsening in a two-dimensional smectic-A.
system New Journal of Physics, 2008, 10, 063025-063041.
 Abukhdeir, N. & Rey, A. Non-isothermal Model for the Direct Isotropic/Smectic-A Liquid Crystalline Transition.
Langmuir, 2009, 25, 11923-11929.
 Huisman, B. A. & Fasolino, A. Influence of latent heat and thermal diffusion on the growth of nematic liquid crystal
nuclei. Physical Review E, APS, 2007, 76, 021706.
講師：貞包 浩一朗氏 (KEK)
題目：The shear effects on a mixture of water / organic solvent / antagonistic salt
Mesoscopic structures, such as lamellar, in a mixture of water, 3-methylpyridine, and antagonistic salt, NaBPh4, are discovered in our recent studies. According to the theoretical investigations by Onuki, hydrophilic and hydrophobic ions tend to adsorb near the interface between water and organic solvent. These ions reduce the interfacial tension between the solvents, and mesoscopic structures are induced. In order to understand the previous experimental results, it is assumed that pairs of hydrophilic (Na+) and hydrophobic ions (BPh4-) play roles of surface-active agent in a mixture of water and 3-methylpyridine. The details of ion distribution, however, have not been clarified experimentally yet in such mixtures. In this study, the effects of shear on a mixture of water / 3-methylpyridine / NaBPh4 are investigated. Then, we found that the mixture at lamellar phase shows shear thickening as is the case with polymer gels. Furthermore, onions or fiber-like structures are also observed by means of Rheo-SALS and Rheo-SANS measurements.
講師：Daniel Beysens (CEA and ESPCI, Paris, France)
題目：Adsorption on colloids and flocculation
Colloidal particles suspended in a binary liquid mixture display many interesting features. For instance, a preferential adsorption occurs, which is more important on the side of the coexistence curve poor in the adsorbed component. Adsorption increases with the proximity of the mixture to the coexistence curve. An aggregation phenomenon, which is reversible with respect to temperature, is observed in the high adsorption regime close to the bulk coexistence. A robust set of observations, involving different colloids and liquid mixtures, are discussed. The above findings are assessed in the light of current theoretical understanding of wetting phenomena. In addition, the recent advances in the dynamics of aggregation of colloids, and the inverse process, fragmentation, are presented.