Marian Smoluchowski in life and science: A brief story

submitted by: icamvid
Jozef Spalek, Jagiellonian University Abstract: I shall be happy to say few words about Marian Smoluchowski, who was a very interesting person, apart from being a great scientist (he died at the age of 45 when returning from a routine Tatry-mountain expedition in 1917, after drinking a contaminated water from Raba river; he did not know that a dead horse was lying in the river upstream; it was the 1st World War time). More importantly, I shall provide an overview of Smoluchowski's...

Theoretical investigations of effective interactions in colloidal suspensions

submitted by: icamvid
Pavel Bryk, Maria Curie-Sklodowska University Abstract: Effective interactions between macroparticles play a key role in predicting the stability of colloidal suspensions. The bare interactions between macroparticles are attractive at larger separations due to the dispersion forces between the atoms forming the colloidal particles. In order to prevent aggregation the colloidal suspension must be stabilized either by charge or sterically. Technical developments during last two decades made...

Repulsive interaction between spherical polyelectrolyte brushes as measured by the kinetics of coagulation

submitted by: icamvid
Matthias Ballauff, University of Bayreuth, Physical Chemistry I Abstract: We propose a new way to determine weak repulsive forces operative between colloidal particles by measuring the rate of slow coagulation. As shown by Smoluchowski in his classical papers, the rate of slow coagulation is directly related to the competition of the repulsion with thermal motion. Since the thermal forces are weak, measurements of the coagulation rate can lead to precise information on repulsive potentials...

Overview of the International Institute for Complex Adaptive Matter (I2CAM)

submitted by: icamvid

Daniel Cox introduces ICAM, I2CAM.

Presented at PSSM Workshop on Liquid Crystals and Colloidal Dispersions
http://www.icmp.lviv.ua/statphys2009/pssm/index.html

Photochemical switching between colloidal photonic crystals at the nematic-air interface

submitted by: icamvid
Stanislav Chernyshuk, Institute of Physics Abstract: A direct observation of the photochemical switching between colloidal crystals with different lattice constants in a liquid-crystal emulsion is reported. Glycerol droplets introduced in a nematic liquid crystal form two-dimensional hexagonal colloidal crystal at the nematic-air interface with a lattice constant depending on the surface tension LCA. We dope an azobenzene derivative into the LC emulsion to modulate the colloidal structures...

Phase separations in mixtures of a liquid crystal and a colloidal particles

submitted by: icamvid
Akihiko Matsuyama, Kyushu Institute of Technology Abstract: We present a mean field theory to describe phase separations in mixtures of a liquid crystal and a colloidal particle. By taking into account a nematic and a smectic A ordering of liquid crystals and a crystalline ordering of colloidal particles, we calculate the phase diagrams on the temperature-concentration plane. We predict various phase separations, such as a smectic A-crystal phase separation and a smectic A-nematic-crystal...

Colloidal nematostatics

submitted by: icamvid
Victor Pergamenshchik, Institute of Physics Abstract: Colloids interact via the nematic director. As the interaction is of a long range, nematic colloids are much closer to electrostatic systems than to standard colloids in isotropic liquids. I will talk about an elastic "charge" and elastic mutipoles, about their interaction and strange properties, e.g., elastic charge is a vector, elastic dipole can be chiral... and more. Presented at PSSM Workshop on Liquid Crystals and Colloidal...

Simulation studies of spherical nanoparticles in mesogenic media

submitted by: icamvid
Matt Glaser, University of Colorado at Boulder Abstract: We describe results from simulations of spherical nanoparticles in a nematogenic solvent consisting of soft spherocylinders. We find that nanoparticles remain well dispersed in the isotropic (low-density) phase of the solvent, but demix into a nanoparticle-poor nematic phase and a nanoparticle-rich isotropic phase at higher pressures. When the nanoparticle-spherocylinder interactions are modified to promote homeotropic anchoring, the...

Shape Controlled Colloidal Interactions in Anisotropic Fluids

submitted by: icamvid
Clayton Lapointe, University of Colorado at Boulder Abstract: Colloidal particles suspended in nematic liquid crystals are known to exhibit highly directional interactions mediated by the elasticity of the liquid crystal. Using lithographically fabricated platelet colloids having equilateral polygonal shapes, we show that colloids with an even number of sides form elastic quadrupoles whereas those with an odd number of sides form elastic dipoles. These qualitatively different interactions...

Molecular dynamics simulation of liquid crystalline polymers: what can be achieved?

submitted by: icamvid
Jaroslav Ilnytskyi, Institute for Condensed Matter Physics Abstract: Polymeric liquid crystals combine the features of both the polymer and liquid crystal. Their fine-tuning is possible on the stage of synthesis which leads to a number of practical applications (high strength plastics, displays, optical data storage). We present some recent results in molecular dynamics simulations of such systems. Liquid crystalline dendrimer is studied in isotropic, nematic and smectic A solvent and we...