LINEAR ENERGY WITH POSITIVE AND NEGATIVE SIGN

The specific linear energy for the case of two-dimensional two-phase systems with a contact line can have a positive value only. For the case of complex capillary systems with bulk, surface and linear phases the linear energy can be either positive or negative. Such behaviour of these quantities, defined by making use of the formalism with the OMEGA-potential, is in close connection with the mechanical equilibrium stability conditions. There is experimental evidence for the above conclusions. 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 formation of holes in amphiphile bilayers.