There is a growing interest in cylindrical structures of hard and soft particles. A promising new method to assemble such structures has recently been introduced by Lee et al. [T. Lee, K. Gizynski, and B. Grzybowski, Advanced Materials 29, 1704274 (2017)], using rapid rotation around a central axis to drive spheres (which are of lower density than the surrounding fluid) towards the axis, and observing different structures as the number of spheres is varied. Here we present comprehensive analytic energy calculations for such self-assembled structures, based on a generic soft sphere model, from which we obtain a phase diagram. It displays interesting features, including peritectoid points. These analytic calculations are complemented by numerical simulations for finite sample sizes with soft spheres.
Theory of rotational columnar structures of soft spheres. J. Winkelmann, A. Mughal, D.B. Williams, D. Weaire, and S. Hutzler, Physical Review E 99 (2), 020602