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

P5.64Wed 711:10-14:00Phase behavior of patchy particles: an integral equationapproachAchille Giacometti, 1 Fred Lado, 2 Julio Largo, 3 Giorgio Pastore, 4 and FrancescoSciortino 51 Dipartimento di Scienze Molecolari e Nanosistemi, Universita Ca Foscari Venezia,Calle Larga S. Marta DD. 2137, I-30123, Venice, Italy2 Department of Physics, North Carolina State University, Rayleigh, Ud States of Am3 Departamento de Fisica Aplicada, Universidad de Cantabria, Santader, Spain4 Dipartimento di Fisica Universita’ di Trieste, Trieste, Italy5 Dipartimento di Fisica, Universita’ La Sapienza Roma, Rome, ItalyMotivated by recent experimental findings in chemical synthesis of colloidal particles, we discussa simple theoretical model – the Kern-Frenkel model – describing a fluid of colloidal sphericalparticles with a pre-defined number and distribution of solvophobic and solvophilic regions on theirsurface. The solvophobic and solvophilic regions are described via a short-range square-well and ahard-sphere potentials, respectively. An integral equations theory is presented to discuss structuraland thermodynamical properties, with particular emphasis on the case of equal distribution of thetwo regions, the so-called Janus particle. We discuss both the case of one and two attractive caps,as a function of the fraction of covered attractive surface, thus interpolating between a squarewelland a hard-sphere potential on changing the coverage. We show that integral equation theoryprovides quantitative predictions in the entire explored region of temperatures and densities fromthe square-well limit down to a significantly small value of the coverage, whose value dependsupon the number of patches. Janus particles can be regarded as a particular case of the one-patchcase in the limit of half-coverage.A Giacometti, F. Lado, J. Largo, G. Pastore, and F. Sciortino, J. Chem. Phys. 131, 174114 (2009)F. Sciortino, A. Giacometti, and G. Pastore, Phys. Rev. Lett. 103, 237801 (2009) A. Giacometti,F. Lado, J. Largo, G. Pastore, and F. Sciortino, J. Chem. Phys. 132, 174110 (2010) F. Sciortino,A. Giacometti, and G. Pastore, Phys. Chem. Chem. Phys. 12, 11869 (2010) R. Fantoni, A.Giacometti, F. Sciortino and G. Pastore, Soft Matter 7, 2419 (2011)64