The present work focuses on the development of thin film nanocomposite (TEN) nanofiltration membranes by formation of co-polyamide layer as solvent stable membranes. The thin layer has been elaborated via in situ interfacial incorporation of TiO2 nanoparticles along with fabrication of co-polyamide network on a polyimide (PI) support. In order to improve the compatibility of nanoparticles inside the polymer matrix, both amine and chloride compounds were employed to functionalize TiO2 nanoparticles. Further, the mechanism of TiO2 surface modifications was presented and proved by FTIR and Energy dispersive X-ray spectroscopy (EDAX) analyses. EDX-mapping analysis were used in order to morphological study of the membranes contain TiO2 nanoparticles. The results showed high loading and uniform dispersion of aminated TiO2 nanoparticles throughout the hybrid co-polyamide thin film. As an understanding concept, intermolecular cross linking reactions as a graphical model were proposed to illustrate the stability of the nanocomposite membranes. Transport properties of the membranes were evaluated by methanol solutions of two different dyes and were interpreted by Donnan Steric Pore Model (DSPM). Interestingly, in comparison with TFC membrane, TEN membranes represented higher methanol flux and good dye rejection in spite of lower swelling degree. Moreover, the type of chemical functions, TiO2 loading and the membrane pore size were considered as the crucial effective factors on the membrane performance. (C) 2013 Elsevier B.V. All rights reserved.