Collagen grafted poly(methyl methacrylate) (PMMA) copolymer (collagen-g-PMMA) and TiO2-coated Ag (Ag@TiO2) core-shell nanoparticles were prepared by graft polymerization and water-in-oil (W/O) emulsion process, respectively, and collagen-g-PMMA/Ag@TiO2 composite was synthesized ilia an ultrasonic irradiation method.. Structure and thermal properties were measured with TEM, UV-vis, FT-IR, and TG/DTA. The results showed the core-shell structure with a crystalline silver core in a size range from 30 to 50 nm in diameter and a shell of amorphous TiO2. The thickness of the shell varied with the concentration of titanium precursor from 2 to 10 nm. The interfacial interactions, such as hydrogen bonds existed between grafted collagen and Ag@TiO2 nanoparticles and played an important role in the formation of the composite. It was found that the composite exhibited a lower infrared emissivity value in the wavelength range from 8 to 14 mu m than that of pure collagen and grafted collagen as a result of strong interfacial synergism forces inside the composite. (C) 2007 Elsevier B.V. All rights reserved.