This study proposes new method for preparing hybrid US nanoparticles in poly(BA-co-GMA-co-GMA-IDA) (PBGM) copolymer membranes with controllable size. PBGM membranes were prepared by soap-free emulsion copolymerization of n-butylacrylate (BA), glycidyl methacrylate (GMA) and 2-methacrylic acid 3-(bis-carboxyniethylamino)-2-hydroxy-propyl ester (GMA-IDA). GMA-IDA chelating groups within the copolymer were the coordination sites for chelating Cd2+, at which nano-sized US nanoparticles were grown. The GMA-IDA mole fractions in PBGM 1, PBGM2, and PBGM3 were 3.97%. 6.41% and 8.79%, respectively, as determined by elemental analysis. Fourier transform infrared spectroscopy spectra were used to elucidate the characteristics of GMA-IDA in PBGM membranes. The size distribution, morphology, and structure of US nanoparticles were measured by transmission electron microscopy (TEM) and X-ray diffraction. TEM observations reveal that the mean diameters of US nanoparticles can be controlled between 3 nm and 6 nm inside the matrix of the PBGM membranes. The UV-vis absorption spectra provide information on the absorption edges, band-gaps and mean diameters. the results of which are consistence with the TEM observations. Photoluminescence spectra show the characteristics of excitation abrsorption of the hybrid membranes. Scanning electron microscopy images reveal the different sizes distributions of US nanopartictes on the surfaces. (C) 2004 Elsevier B.V. All rights reserved.