The effect of particle shape in self-assembly and self-organisation of soft materials

The ability of atomic, colloidal, and nanoparticles to self-organize into highly ordered crystalline structures makes the prediction of crystal structures in these systems an important challenge for science. The question itself is deceivingly simple: assuming that the underlying interaction between constituent particles is known, which crystal structures are stable. In this talk, I will describe a Monte Carlo simulation method [1] combined with a triangular tesselation method [2] to describe the surface of arbitrarily shaped particles that can be employed to predict close-packed crystal structures in colloidal hard-particle systems. I will show that particle shape alone can give rise to a wide variety of structures with unusual properties [3-6], e.g., photonic band gap structures by using mixtures of spheres and tetramers or highly diffusive crystals in the case of truncated cubes or binary hard-sphere mixtures. Finally, I will show that the number of possible structures can even be enlarged further by combining the choice of particle shape with external fields, like confinement [7].

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[2] J. de Graaf, R. van Roij and M. Dijkstra, Phys. Rev. Lett. 107, 155501 (2011).
[3] A. P. Gantapara, J. de Graaf, R. van Roij, and M. Dijkstra, Phys. Rev. Lett. 111, 015501 (2013)
[4] F. Smallenburg, L. Filion, M. Marechal, and M. Dijkstra, Proceedings of the National Academy of Sciences 109, 17886 (2012).
[5] L. Filion, M. Hermes, R. Ni, E. C. M. Vermolen, A. Kuijk, C. G. Christova, J. C. P. Stiefelhagen, T. Vissers, A. van Blaaderen, and M. Dijkstra, Phys. Rev. Lett. 107, 168302 (2011).
[6] S. Dussi and M. Dijkstra, Nature Communications 7, 11175 (2016).
[7] B. de Nijs, S. Dussi, F. Smallenburg, J.D. Meeldijk, D.J. Groenendijk, L. Filion, A. Imhof, A. van Blaaderen, and M. Dijkstra, Nature Materials 14, 56-60 (2015).