Influence of polymer molecular weight on the properties of in situ synthesized silver–methylcellulose nanocomposite films with a CO₂ laser

Abstract

We investigate the influence of polymer molecular weight on the properties of silver–methylcellulose (Ag–MC) nanocomposite films synthesized by the irradiation of a CO₂ laser. Although the reduction power of MC with a smaller molecular weight turns out to be stronger than that with a larger molecular weight in the solution phase, we do not see such a clear difference when MC is in the matrix phase. For the 30 s irradiation at the laser power of 0.8 W, the size of Ag nanoparticles (NPs) in the two types of MC matrix is similar, and it is about 30 nm. However, for the longer irradiation time at the same laser power, aggregation of Ag NPs set in, and it is more serious for the Ag–MC film with MC of larger molecular weight. We also carry out the antibacterial test with the Ag–MC films, and find that the Ag–MC film synthesized at the lower laser power and shorter irradiation time generally exhibits a stronger antibacterial effect.