Properties of the solvation force of a two-dimensional Ising strip in scaling regimes

We consider the d = 2 Ising strip with surface fields acting on boundary spins. Using the properties of the transfer matrix spectrum we identify two pseudotransition temperatures and show that they satisfy similar scaling relations as expected for real transition temperatures in strips with d>2. The solvation force between the boundaries of the strip is analysed as a function of temperature, surface fields and the width of the strip. For large widths, the solvation force can be described by scaling functions in three different regimes: in the vicinity of the critical wetting temperature of the 2D semi-infinite system, in the vicinity of the bulk critical temperature and in the regime of weak surface fields, where the critical wetting temperature tends towards the bulk critical temperature. The properties of the relevant scaling functions are discussed.