Abstract: Described are methods for forming thin, pinhole-free conformal metal layers on both conducting and non-conducting surfaces. The formed metal films are useful as seed layers for further deposition of metal using conventional techniques like electroplating, and provide specific advantages for non-conducting surfaces, which are otherwise unsuitable for electroplating without the presence of the formed metal films. Unlike electroplating, the disclosed methods, however, do not require the presence of a voltage or external electric field at the surface, but form the metal films through an electroless technique using electrostatic interactions between negatively charged nanoparticles and a positively charged surface. In addition, the disclosed methods are compatible with solution phase processing and, thus, eliminate the need to transfer the surfaces into a vacuum chamber for a chemical or physical vapor deposition to form a metal layer.