In this study, we report the synthesis of thin film nanocomposite (TFN) membranes by interfacial\npolymerization (IP) on porous polysulfone (PSf) hollow fiber membrane supports. We also investigate the\nsynthesis of carboxylated TiO2 (C-TiO2) and hydroxylated TiO2 (H-TiO2) nanoparticles using a simple\ntechnique and evaluate the performance of the TFN membranes incorporated with these nanoparticles\nfor water vapor separation. Comparative studies were carried out on membranes with and without the\nincorporation of nanoparticles (TFN and TFC) for water vapor separation. Aqueous 3,5-diaminobenzoic\nacid (DABA)/nanoparticles mixture solutions and organic trimesoyl chloride (TMC) were used in the IP\nprocess. The reaction between these two monomer solutions at the interfaces of PSf hollow fiber\nsubstrates resulted in the formation of the TFN membranes. Functionalized TiO2 nanoparticles (TiO2NPs)\nwith a size of about 60 nm were used for the fabrication of the TFN hollow fiber membranes. These TFN\nmembranes were characterized using different modern techniques and evaluated in comparison with\nthe tidy TFC membranes. Their performances were evaluated based on the water vapor permeability and\nselectivity. Experimental results indicate that the carboxylated TiO2 nanoparticle (C-TiO2NPs)\nincorporated membrane shows improved performance compared to other membranes. By changing the\nnanoparticles, better hydrophilicity was obtained; the contact angle was decreased from 90 (PSf) to 46\n(TFN) and the water vapor permeance was increased from 780 GPU (TFC) to 1131 GPU (TFN) with high\nselectivity being maintained (from 115 to 548) when the C-TiO2NPs content was 0.05 (wt%).