Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 16: Poster: Colloids and Complex Liquids

CPP 16.9: Poster

Tuesday, March 27, 2012, 18:15–20:45, Poster A

Fluid-Fluid and Fluid-Solid transitions in the Kern-Frenkel model from Barker-Henderson thermodynamic perturbation theory — •Christoph Goegelein¹, Flavio Romano², Francesco Sciortino³, and Achille Giacometti⁴ — ¹MPI für Dynamik und Selbstorganisation, Goettingen — ²Physical and Theoretical Chemistry Laboratory, Oxford University (UK) — ³Dipartimento di Fisica and CNR-ISC, Sapienza Universita di Roma, Piazzale A. Moro 5, 00185 Roma, Italy — ⁴Dipartimento di Scienze dei Materiali e Nanosistemi, Universita Ca' Foscari Venezia, Calle Larga S. Marta DD2137, I-30123 Venezia, Italy

We study the Kern-Frenkel model for patchy colloids using Barker-Henderson thermodynamic perturbation theory. The model describes a fluid where hard sphere particles are decorated with one patch, so that they interact via a square-well potential if they are sufficiently close one another, and if patches on each particle are properly aligned. Both the gas-liquid and fluid-solid phase coexistences are computed and contrasted against Monte-Carlo simulations results. We find that the perturbation theory describes rather accurately numerical simulations all the way from a fully covered square-well potential down to the Janus limit (half coverage). In the region where numerical data are not available (from Janus to hard-spheres), the method provides estimates of the location of the critical lines that could serve as a guideline for further efficient numerical work at these low coverages. A comparison with other techniques, such as integral equation theory, highlights the important aspect of this methodology in the present context.