Original antifouling strategy: Polypropylene films modified with chitosan-coated silver nanoparticles

Abstract

A new coating strategy of polypropylene (PP) films with silver nanoparticles (AgNPs) is proposed to obtain surfaces with antifouling properties. As a first step, the photograft polymerization is used to produce polyacrylic acid-grafted PP (PAA-grafted PP) films. A green AgNP synthesis is used by thermal reduction of AgNO3 with amino groups of chitosan (CS), which controls ion diffusion and stabilizes nanoparticles. AgNP/CS complexes are adsorbed on PAA-grafted PP by electrostatic interactions, yielding AgNP/CS-coated PP films. These films show an excellent antimicrobial activity, even for AgNP contents as low as 0.08 wt %, reducing more than 4 log units in the viable Staphylococcus aureus concentration or inducing Escherichia coli death. This trend is consistent with an adequate amount of small AgNP adsorbed in an organized manner within a thin surface layer. Therefore, the antimicrobial activity of this film seems to be more than promising, used as an active surface for a wide range of applications.