Effect of surface physicochemical properties on the water film confined within a nanogap was investigated. The film thickness and friction force were measured by the Relative Optical Interference Intensity (ROII) method and a UMT-2MT tribotester. It was found that the confined water film formed the thicker lubricate film than the prediction of elastic-isoviscous lubrication theory. Experimental results indicate that the higher the solid/water interfacial energy is, the thicker lubricate film the highly viscous "interphase'' water layer forms and the lower the friction force is. (C) 2008 Published by Elsevier B.V.