Presented at the International Congress on Membranes and Membrane Processes (ICOM), Seoul, Korea, 21–26 August 2005. 0011-9164/06/$– See front matter © 2006 Elsevier B.V. All rights reserved Desalination 192 (2006) 262–270 Preparation and characterization of novel porous PMMA-SiO 2 hybrid membranes Muhammad Ali Zulfikar a , A. Wahab Mohammad a *, Nidal Hilal b a Department of Chemical and Process Engineering, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia Tel. +60 (3) 8921-6410; Fax: +60 (3) 8921-6148; email: wahabm@vlsi.eng.ukm.my b Centre for Clean Water Technologies, School of Chemical, Environmental and Mining Engineering, The University of Nottingham, NG7 2RD, UK Received 17 March 2005; accepted 15 September 2005 Abstract Poly(methyl methacrylate) (PMMA)-SiO 2 composite membranes were prepared by casting ternary solutions obtained by adding additional amounts of TEOS to PMMA solutions. Methods to obtain an intimate dispersion of the inorganic particles in the PMMA solutions were developed. Various samples of hybrid membranes were prepared by varying some of the preparative parameters such as the PMMA solvent (tetrahydrofuran, and N,N-dimethyl formamide) and the PMMA/TEOS ratio in the ternary solution. Membranes were also cast from a binary solution of PMMA and solvent for comparison. The membranes were characterized by water permeability, scanning electron microscope observations, DSC and TGA analysis and ultrafiltration tests. The effects of the above-mentioned preparative parameters on the structure, thermal behavior, flux and dextran retention properties of the membranes are discussed. Keywords: Organic-inorganic membranes; Poly(methyl methacrylate); TEOS; Ultrafiltration properties 1. Introduction The possibility of combining properties of organic and inorganic materials was explored several years ago. The presence of finely dis- persed inorganic particles in the polymer matrix *Corresponding author. has proven to be very useful in the improvement of membrane performance. Many new types of organic/inorganic hybrid materials have the potential to combine the desired properties of inorganic and organic systems, improving the mechanical and thermal properties of inorganic ones with the flexibility and ductility of organic