Thermodynamic Stability of Medium with an Alternating-Sign Pressure
  The thermodynamic medium is treated as homogeneous phase equilibrium with a special feature: the pressure of one phase is positive and the pressure of the other is negative. From this point of view such medium is neither mixture, usual solution nor gel (or sol as a whole) regardless its components (solvent and dissolved substances). To base this statement the theoretical investigation of the conditions of equilibrium and stability of the medium with sign-alternative pressure is carried out under using the thermodynamic laws and the Gibbs' equilibrium criterion. Thermal radiation and condensate are claimers on the medium with alternating-sign pressure. 
V.I. Laptev
physics.gen-ph