Mesoporous MCM-41 silica spheres were synthesized via modified Stober method and modified by silylation. The MCM-41 pore structures, surface properties and morphological features before and after modification were examined by XRD, SEM, TEM, FT-IR, TGA, Si-29 CP/MAS NMR and nitrogen adsorption-desorption. The results showed that the obtained MCM-41 silica had ordered mesoporous structure and spherical morphology. After silylation, the surface property of MCM-41 silica changed from hydrophilic to hydrophobic, whereas the MCM-41 framework and morphology were retained. The calcined and modified MCM-41 spheres were incorporated into a polydimethylsiloxane (PDMS) matrix, separately. It is clearly shown from the SEM image that modification of MCM-41 spheres greatly enhanced its interfacial adhesion with the polymer. The filled membrane was firstly used for pervaporation separation of dimethylcarbonate/methanol azeotropic mixture and displayed superior pervaporation performance than pure PDMS membranes. (C) 2012 Elsevier B.V. All rights reserved.