Unbinding transitions and phase separation of multicomponent membranes

Multicomponent membranes in contact with another surface or wall are studie d by a variety of theoretical methods and Monte Carlo simulations. The memb ranes contain adhesion molecules which are attracted to the wall and, thus, act as local stickers. It is shown that this system undergoes lateral phas e separation leading to discontinuous unbinding transitions if the adhesion molecules are larger than the nonadhesive membrane components. This proces s is driven by an effective line tension which depends on the size of the s tickers and arises from the interplay of shape fluctuations and sticker clu sters.