Monte Carlo simulation of a binary mixture on the surface of a sphere: lateral phase transition and pattern formation

Phase diagram of SALR fluids on spherical surfaces

We investigate the phase diagram of a fluid of hard-core disks confined to the surface of a sphere and whose interaction potential contains a short-range attraction followed by a long-range repulsive tail (SALR). Based on previous work in the bulk we derive a stability criterion for the homogeneous phase of the fluid, and locate a region of instability linked to the presence of a negative minimum in the spherical harmonics expansion of the interaction potential. The inhomogeneous phases contained within this region are characterized using a mean-field density functional theory. We find several inhomogeneous patterns that can be separated into three broad classes: cluster crystals, stripes, and bubble crystals, each containing topological defects. Interestingly, while the periodicity of inhomogeneous phases at large densities is mainly determined by the position of the negative minimum of the potential expansion, the finite size of the system induces a richer behavior at smaller densities.

Self-assembly of binary nanoparticles on soft elastic shells

The self-assembly behaviors and phase transitions of binary nanoparticles (NPs) adsorbed on a soft elastic shell are investigated through molecular dynamics simulation. The conformations of adsorbed binary NPs depend on the bending energy K(b) of elastic shell and the binding energy D0 between the NPs and the elastic shell. The ordered structures of binary NPs are observed at the moderate adhesive strength and bending energy, in which the small NPs are located near the vertices of regular pentagons as well as the large NPs are distributed along the sides of the regular pentagons. The shape of soft elastic shell can be adjusted by adding the adsorbed binary NPs, and this investigation can provide an effective way to regulate and reshape surfaces or membranes with the sizes in the micrometer range or smaller.