STATISTICAL-MECHANICS OF 3-DIMENSIONAL VESICLES

We consider a lattice model of three-dimensional vesicles in which the boundary of the vesicle is a self-avoiding plaquette surface, homeomo rphic to a sphere. Surfaces with fixed area can enclose a variety of d ifferent volumes and we associate a fugacity with the enclosed volume to mimic the effect of a pressure difference across the surface. Pairs of plaquettes which share a common edge can be in the same plane or n ormal to each other and we associate a fugacity with adjacent pairs of plaquettes at right angles to represent a surface stiffness term. We discuss the behaviour of the surfaces in the infinite surface area lim it, as a function of these two fugacities.