Using the extended McMillan's mean field approach with anisotropic forces a numerical study of the surface tension, disjoining pressure and layer compression of free-standing smectic film composed of decylcyanobiphenyl (10CB) molecules immersed in water has been carried out. We obtained that the smectic-A-isotropic transition occurs through a series of layer-thinning transitions causing the films to thin one layer at time, as well as a stepwise reduction and increase of the values of the surface tension and disjoining pressure per 10CB molecule as the temperature is raised to the isotropic value. Reasonable agreement between the theoretically predicted and the experimentally obtained data has been obtained. (C) 2014 Elsevier B.V. All rights reserved.