Dewetting of a heated surface by an evaporating liquid film under conjoining/disjoining pressures

In the present work we consider a model for the evolution of a thin nonpola r liquid film an a coated solid surface under the action of attractive and repulsive molecular forces governed by a 3-4 power-law potential, rather th an the Lennard-Jones 3-9 potential employed for an ideal plane interface (m olecularly clean and smooth). The model is used for both volatile and nonvo latile isothermal liquid films. It is shown that in the nonvolatile case th e evolution results in the emergence of static steady states consisting of liquid ridges separated by very thin films. A supercritical bifurcation fro m the trivial state is shown to be possible in the presence of repulsive fo rces, while in the presence of only attractive forces the bifurcation is su bcritical. In the evaporative case the long-time evolution of the film is s hown to lead to its flattening and then to its apparent vanishing. Several scenarios for the film disappearance are found. A relationship between the rate of expansion of the dry spot and the apparent contact angle is examine d. The effect of thermocapillarity on the film evolution is also considered . (C) 1999 Academic Press.