[Zurück]

S. Wagner, G. Kahl:
"Structure and thermodynamics of elliptic patcy particles";
Poster: 5th International Soft Matter Conference (ISMC2019), Edinburgh; 03.06.2019 - 07.06.2019; in: "Conference Booklet of the 5th International Soft Matter Conference (ISMC2019)", (2019), S. 41.

In an effort to investigate colloidal particles that feature both shape anisotropy aswell as surface decorations we put forward a novel model for elliptic patchy colloids.Considering a two-dimensional geometry, the bodies of our particles are impenetrableellipses (of aspect ratioκ) that can be decorated on their (co-)vertices by up to fourpatches. The latter ones range over a certain patch amplitudeθon the surface of theosculating circles defined for the (co-)vertices of the ellipse. The opening angle of thepatches is limited by the accuracy with which the osculating circle represents the ellipticsurface. Within the patch region the interaction is assumed to be constant in depthand range. Thus our model can be considered as a straightforward extension of theKern-Frenkel model for circular (spherical) patchy particles [1].In order to use this model in Monte Carlo simulations we have used (i) for the undeco-rated bodies of our particles the overlap criterion of two ellipses put forward by Vieillard-Baron [2] and (ii) the patch-patch interaction criterion used for the original Kern-Frenkelmodel. Using 1∼260 particles in Monte Carlo simulations in the isobaric-isothermal andin the canonical ensemble, we have studied the spatial and the orientational order aswell as the equation-of-state. In an effort to better accommodate the emerging orderedphases we have used a simulation box which can vary both in shape and in area. Follow-ing previous investigations on undecorated elliptic particles [3] we have considered threeκvalues, namelyκ= 2,4 and 6.Varying systematically the pressure and the temperature and choosing different patchdecorations we investigate the emergence of the disordered and the ordered phases,which are the result of a trade-off between energetic and entropic contributions to thethermodynamic potential. The ordered particle arrangements were classified using thespatial radial distribution and suitably chosen orientational correlation functions [3] andappropriate order parameters: in particular we were interested in the occurrence of thenematic phases, of plastic crystals and of hexatic phases.First results for the structure and the equation of state for a system of particles withtwo symmetric patches located at the co-vertices have been published recently [4].[1] N. Kern, D. Frenkel, The Journal of Chemical Physics118.21, 9882 (2003)[2] J. Vieillard-Baron, The Journal of Chemical Physics56.10, 24501 (1972)[3] A. Cuesta, D. Frenkel, Physical Review A42.4, 2126 (1990)[4] S. Wagner, G. Kahl, arXiv:1902.08097 [cond-mat.soft]

Patchy Particles, Monte Carlo

https://publik.tuwien.ac.at/files/publik_287106.pdf