Amphiphilic functional copolymers have been successfully synthesized and used for the supercritical CO2-mediated design of Pd supported catalysts. First, a new palladium complex soluble in supercritical CO2 has been prepared by ligand exchange, in Freon 113 or supercritical CO2, between an amphiphilic functional copolymer and a metal precursor (palladium acetate Pd(OAc)(2)). Then, the solubility behavior of this copolymer/Pe supramolecular complex has been studied in supercritical CO2. The amphiphilic functional gradient copolymer used in this work, poly(1,1,2,2-tetrahydroperfluorodecylacrylate-co-acetoacetoxyethylmethacrylate) copolymer (poly(FDA-co-AAEMA)), was purposely synthesized by controlled radical polymerization in trifluorotoluene or in supercritical CO2. The fluorinated monomer units (FDA) impart CO2-philic properties to the copolymer while the acetoacetoxy monomer units (AAEMA) bring the complexing character to the copolymer. After reduction of the complex under hydrogen atmosphere, well-dispersed small nanoparticles of Pd degrees (2-6 nm diameter size range) were obtained within the copolymer matrix. The copolymer/Pd-II supramolecular complex was also used as an impregnation agent for the preparation of supported catalysts. Thus, a mesoporous silica material was impregnated by the complex in supercritical CO2. After reduction, a composite material composed of nanoparticles of Pd degrees (2-9 nm size) evenly distributed in the pores of the silica matrix was obtained. Finally,the catalytic activity of the prepared Pd degrees@SiO2 supported catalyst was evaluated in the Heck reaction. (C) 2015 Elsevier B.V. All rights reserved.