Size-controlled in situ synthesis of metal–polymer nanocomposite films using a CO₂ laser

Abstract

In situ synthesis of metal–polymer nanocomposite films by irradiating a CO₂ laser for several seconds is a new alternative to fabricate metal–polymer nanocomposite films. The main features of this method are that the number density of the synthesized metal nanoparticles is very high so that the optical density easily exceeds 0.5 ~ 1.5 for the film thickness of ~ 200 nm, and owing to the short fabrication time and the use of non-focused laser beam, large-scale processing is possible. For this technique to be applicable for a variety of purposes, an important question is how and how much we can control the film properties. In this work, we demonstrate that the size and size distribution of metallic nanoparticles in the synthesized nanocomposite films can be well controlled by the choice of the laser power and irradiation time as well as the concentrations of nanoparticle precursor. Properties of the synthesized films can be roughly understood by considering the diffusion of metallic ions, atoms, and nanoparticles in the polymer film under the elevated temperature induced by the CO₂ laser.