Selective implantation of gold nanoparticles onto the surface on one side of a self-standing polymer film

A novel method of highly-selective implantation of gold nanoparticles onto one surface of a polymer thin film with sub-micrometer thickness is demonstrated. The poly(methyl methacrylate) (PMMA) film of about 270 nm thickness, where gold nanoparticles (AuNPs) of ∼20 nm diameter were exclusively implanted on one surface, was successfully fabricated. The preparation was carried out by using a water-organic interface at room temperature. The resultant film was self-standing in a loop of as large as about 3 cm diameter. AuNPs were located only at the surface on one side of the PMMA film, which is confirmed using transmission absorption spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. After annealing the PMMA film incorporating AuNPs in hot water, only the surface on one side of the film, where AuNPs were located, became conductive.