Nonlinear elastic model for faceting of vesicles with soft grain boundaries

TL;DR

This paper presents an elastic model to understand how vesicles with elastic heterogeneities develop faceted shapes, highlighting the role of softer regions and crystalline defects in shaping vesicle morphology.

Contribution

The study introduces a nonlinear elastic model incorporating heterogeneities and uses simulated annealing to explore vesicle faceting beyond traditional icosahedral shapes.

Findings

Faceting occurs in softer vesicle regions.

Crystalline defects influence vesicle shape.

Polyhedral vesicles other than icosahedra are possible.

Abstract

We use an elastic model to explore faceting of solid-wall vesicles with elastic heterogeneities. We show that faceting occurs in regions where the vesicle wall is softer, such as areas of reduced wall thicknesses or concentrated in crystalline defects. The elastic heterogeneities are modeled as a second component with reduced elastic parameters. Using simulated annealing Monte Carlo simulations we obtain the vesicle shape by optimizing the distributions of facets and boundaries. Our model allows us to reduce the effects of the residual stress generated by crystalline defects, and reveals a robust faceting mechanism into polyhedra other than the icosahedron.