Crumpling of fluid vesicles

Models of athermal self-avoiding fluid and polymerized vesicles have been investigated by Monte Carlo simulations. There is no evidence for crumpling of polymerized vesicles, and the squared radius of gyration is proportional to the number of monomers on the surface, ${\mathit{R}}^2$∼N. Fluid vesicles, on the other hand, exhibit a crumpled shape and ${\mathit{R}}^2$∼${\mathit{N}}^{0.8}$. We explain our model dynamics for fluid surfaces. The time-dependent mean-squared displacement ${\mathit{r}}^2$(t) of a monomer on a fluid surface is ∼${\mathit{t}}^{0.8}$, whereas ${\mathit{r}}^2$(t)∼ √t for polymerized vesicles. The corresponding configurational correlation times are τ∼N for fluid and τ∼${\mathit{N}}^2$ for polymerized vesicles.