LINEAR ENERGY WITH POSITIVE AND NEGATIVE SIGN

The specific linear energy for the case of two-dimensional two-phase s ystems with a contact line can have a positive value only. For the cas e of complex capillary systems with bulk, surface and linear phases th e linear energy can be either positive or negative. Such behaviour of these quantities, defined by making use of the formalism with the OMEG A-potential, is in close connection with the mechanical equilibrium st ability conditions. There is experimental evidence for the above concl usions. The methods of determining the specific linear energy for the case of a black film in contact with a bulk solution are reviewed. The two-dimensional case is illustrated by examining the fluctuational fo rmation of holes in amphiphile bilayers.