Size and interface effects on kinetic and thermodynamic properties (shear viscosity [eta(T,D)], surface tension [gamma(T,D)] and thermal expansion coefficient [beta(T,D)]) of thin polymer films at temperature T have been modeled based on free volume model and size-dependent function for mean-square displacement of molecules in thin polymer films at glass transition temperature a sigma(2)(g)(D), where D denotes the thickness of thin films. In terms of these models, eta(TD), beta(TD) and gamma(TD) functions are predicted to decrease or increase as D decreases in comparison with the corresponding bulk values, depending on free surface effect and film/substrate interface interaction strength. The predictions are in agreement with available experimental measurements of polystyrene and polybutadiene thin films. (c) 2006 Elsevier B.V. All rights reserved.