Poly[N-isopropylacrylamide-co-[2-(methylthio) ethyl methacrylate]], poly(NIPA-co-MTEMA) gels were prepared by free radical polymerization in aqueous solution. The homogeneous and heterogeneous gels were prepared by using 10 mM MTEMA in 5.0%(v/v) ethanol at 10 degrees C and 30 mM MTEMA in 20%(v/v) ethanol at 50 degrees C, in 1.0 and 1.5M NIPA solution, respectively. Homogeneous and heterogeneous gels had swelling ratios at 540 6 28% and 551 +/- 37%, respectively. The extraction of Au(III) ion was studied in batch method. The optimum pHs for the extraction of Au(III) by homogeneous and heterogeneous gels were 1-3 and 1-5, respectively. The suitable extraction time was 3 h at 50 degrees C when using a rod-shaped copolymer (0.7 cm diameter and 1 cm length). The adsorption behavior obeyed the Langmuir and Freundlich isotherms. The maximum sorption capacities of Au(III) onto homogeneous and heterogeneous gels were 62.8 and 322 mu mol/g, respectively. The desorption equilibrium was reached within 2-3 h at 10 degrees C by 0.1M thiourea in 5%(v/v) HCl. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 309-83108, 2011