The method of preparing Ag/PPy films of surface enhanced Raman scattering is studied by using an ion self-assembled method. The Ag nanoparticles are directly self-assembled to the surface of a conductive polymer film（ PPy） to form an Ag/PPy film for the substrate of surface enhanced Raman scattering. After the PPy films are pre-treated with ammonia

increasing self-assembly time of Ag nanoparticles in AgNo

3

solution

results in a increasing density of Ag nanoparticles; A 532 nm wavelength continuous laser is used to test the tensile properties of Ag/PPy films of a different self-assembly time. The results show that Raman peak at 1 585 cm

-1

fro

m PPy films is increased up to 30 times. In addition

a trace amount of melamine can be detected in Ag/PPy film

but not detected in PPy film. This preparation method of SERS thin films can be widely used in fast detection of biomedicine

food and other fields.