In this study, a two-fluid (TF) model is developed for two-phase flows in proton exchange membrane fuel cells (PEMFCs). The drag force and lift force between gas and liquid phase are considered in N-S equations. In addition, a simplified model is introduced to obtain the liquid water droplet detachment diameter on the gas diffusion layer (GDL)/channel interface which involves the properties of the GDL/channel interface (contact angle and surface tension). The TF model and the simplified model for the prediction of water droplet detachment diameter on GDL/channel interface are validated by the comparison between the experimental data and the model results, respectively. The effect of the properties of GDL/channel interface (contact angle and surface tension) on two-phase behavior in PEMFCs is investigated, The results show that a high contact angle and a low surface tension are advantageous for liquid water removal in the gas channel and the GDL even though a low surface tension will lead to a low capillary force in the GDL. (c) 2006 Elsevier B.V. All rights reserved.