IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Dipolar colloids system: string- fluid regime?
Autor/es:
M. E. BRITO; M. A. CARIGNANO; V.I. MARCONI
Lugar:
Río DE Janeiro
Reunión:
Otro; ICAM FAPERJ School 2014; 2014
Institución organizadora:
ICAM
Resumen:
Particles with directional interactions have attracted the attention of many scientists during last years. These interacting particles can form a wide variety of anisotropic structures and they represent a building block for the design of new complex structured materials [1]. A classic example of systems with directional interactions are electro- and magnetorheoligical fuids, which are suitable for mechanical engineering as well as optical applications. Dipolar colloids form one of the simplest materials presenting anisotropic interactions. This system self assembles resulting in several phase transitions. Three different regimes are obtained while decreasing temperature: fluid, string- fluid and string-gel [2], being the string- fluid a remarkable and an arguable result. We investigate the di fferent regimes of a highly diluted dipolar colloidal system with implicit solvent. Each colloid is build by a big particle with two oppositely charged smallspheres embedded, i.e. with a constrained nite dipole. Unlike previous works [2], we use a continuous model for the particle-particle interactions and we perform stochastic dynamicssimulations. We present a phase diagram, density vs temperature [3]. We focus on the controversial string-fl uid regime, obtained as well with our model and method, in accordance with previous works based on theoretical analysis and Monte Carlo simulations [4].[1] Anisotropy of building blocks and their assembly into complex structures, S. C. Glotzerand M. J. Solomon, Nature Mater., 6:557-562, (2007).[2] Phase diagram for stimulus-responsive materials containing dipolar colloidal particles,A. Goyal, C. K. Hall and O. D. Velev, Phys. Rev. E 77, 031401 (2008).[3] Master Degree in Physics Thesis, by Mariano E. Brito. FaMAF-UNCordoba, August2013.[4] String-fluid transition in systems with aligned anisotropic interactions, P. C. Brandt, A.V. Ivlev and G. E. Morll, J. Chem. Phys., 132, 234709 (2010)