We propose an optimization method for the inverse structural design of self-assembly of anisotropic patchy particles. The anisotropic interaction can be expressed by the spherical harmonics of the surface pattern on a patchy particle, and thus, arbitrary symmetries of the patch can be treated. The pairwise interaction potential includes several to-be-optimized parameters, which are the coefficients of each term in the spherical harmonics. We use the optimization method based on the relative entropy approach and generate structures by Brownian dynamics simulations. Our method successfully estimates the parameters in the potential for the target structures, such as square lattice, kagome lattice, and dodecagonal quasicrystal.

The interplay between the positional order and orientational order of dipole patchy particles on a sphere.

The positional order of the particles in a dodecagonal quasicrystal can be seen from the triangulated network, whose vertex is a dodecagonal motif made of nineteen particles.

We investigate the assembly of the dipole-like patchy particles confined to a spherical surface by Brownian dynamics simulations. The surface property of the spherical particle is described by the spherical harmonic Y10, and the orientation of the particle is defined as the uniaxial axis. On a flat space, we observe a defect-free square lattice with nematic order. On a spherical surface, defects appear due to the topological constraint. As for the director field, four defects of winding number +1/2 are observed, satisfying the Euler characteristic. We have found many configurations of the four defects lying near a great circle. Regarding the positional order for the square lattice, eight grain boundary scars proliferate linearly with the sphere size. The positions and orientations of the eight grain boundary scars are strongly related to the four +1/2 defect cores.