We have developed a new technique for the preparation of conducting nanoparticle films, which consisted of gold nanoparticles networked with binding molecules such as butanethiol, pentanehtiol, hexanethiol, and heptanethiol, on a polystyrene substrate through a one-step straightforward procedure. The film conductivity became significantly higher with a decrease in the alkylchain length, depending on the number of carbon atoms (n) of the binder molecule between adjacent Au nanoparticles, in which it was changed from an insulator (n > 10) to conductor (n = 4). The film resistivity (2.1 mu Omega cm) prepared using butanethiol corresponds to that of planar gold (1.3 mu Omega cm). (c) 2006 Elsevier B.V. All rights reserved.