Discontinuous unbinding transitions of flexible membranes

The adhesion of membranes is often governed by an interaction potential which exhibits a potential barrier at intermediate membrane separations. At low temperatures, the membranes are trapped by the barrier. As the temperature is increased, thermally-excited shape fluctuations act to reduce the strength of this barrier until the membranes undergo an unbinding transition. This transition is discontinuous and continuous for strong and for weak potential barriers, respectively. Thus, the membranes can tunnel through weak barriers but remain trapped by strong ones. A simple criterion in terms of the parameters of the interaction potential is derived by which one can distinguish these two regimes.