Simulated bilayer from floppy to hole and topological fluctuations

TL;DR

This study uses coarse-grained simulations to explore how bilayer topology changes from floppy to hole formation, investigating the role of Gaussian curvature fluctuations in this process.

Contribution

It introduces a simulation model that captures topological fluctuations in bilayers across different states, linking curvature distributions to topology changes.

Findings

Gaussian curvature distributions evolve with bilayer state

Topological fluctuations are associated with curvature changes

Model effectively represents amphiphile bilayer behavior

Abstract

Simulations of a bilayer in a liquid solvent in the full range of areas from the floppy to the extended state also show the hole/tunnel spontaneous formation. Whether this change of topology is preceded by topological fluctuations of the Gaussian curvature $K(x,y)$ is an open question. Probability distributions of Gaussian curvature are transformed into those of the ordered inverse radii; these new shapes show a gradual change along the isotherm. The model of Max-Planck group with 5 beads is used, amended to represent amphiphiles in the spirit of the "coarse-grained" or "Martini" force field.