MONTE-CARLO SIMULATION OF CURVATURE-ELASTIC INTERFACES

We introduce a new Monte Carlo simulation technique for the equilibrat ion of curvature-elastic interfacial systems such as surfactant films dissolved in bulk media. The method is based on a continuous represent ation of the interfaces and can accurately evaluate all relevant surfa ce averages of the curvature Hamiltonian. We apply the method to spong e-like surfactant systems with the standard Hamiltonian, where the onl y parameters are the bending and saddle-splay moduli, kappa and kappaB AR. Random bicontinuous surface states are found to be stable for low bending rigidity and small negative saddle-splay modulus, justifying t he use of Gaussian ensembles as approximations to real interfacial ens embles. Topological changes of the random sponge states as a function of the ratio kappaBAR/kappa are analyzed; the results over a wide rang e Of kappa suggest that only this universal ratio determines whether t he final states resemble disordered minimal surfaces, disordered lamel lar, or connected parabolic geometries.