The hydrophobic properties of gamma-Al2O3 membrane have been obtained by grafting. uoroalkylsilane (FAS) on the surface of the membrane. The following grafting parameters were studied: the eroding time of the original membrane, the grafting time, the concentration of FAS solution and the multiplicity of grafting. Hydrophobicity of the membranes was characterized by contact angle (CA) measurement. The thermogravimetric analysis (TGA) was used to investigate the weight loss process (25-800 degrees C) of the. uoroalkylsilane grafted on Al2O3 powders under different grafting conditions. The morphologies of the membranes modified under different parameters were examined by field emission scanning electron microscopy (FE-SEM) and the surface roughness (Ra) was measured using white light interferometers. A needle-like structure was observed on the membrane surface after modi. cation, which causes the change of Ra. On the results above, we speculated a model to describe the reaction between FAS and gamma-Al2O3 membrane surface as well as the formed surface morphology. (C) 2009 Elsevier B.V. All rights reserved.