Antimicrobial coatings based on poly(dimethyl siloxane) and silver nanoparticles by solution blow spraying

Abstract

Antimicrobial coatings of poly(dimethyl siloxane) with silver nanoparticles (PDMS/AgNPs) were produced by solution blow spraying (SBSp), an adaptation of the solution blow spinning technique (SBS). Firstly, AgNPs were synthesized by the Turkevich method and characterized by dynamic light scattering (DLS), ultraviolet-visible spectroscopy (UV–vis), agar disk diffusion tests against Escherichia coli and Staphylococcus aureus, and toxicity to Artemia salina. Further, the PDMS/AgNPs coating was prepared in two steps by deposition of PDMS solution in hexane (2:1) over the substrate, and then, five depositions, in intervals of 7.5 min each, of the colloidal dispersion of AgNPs onto partially cured PDMS surface. The neat PDMS and PDMS/AgNPs coatings were characterized by inductively coupled plasma atomic emission spectrometry (ICP-AES), atomic force microscopy (AFM), contact angle and scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDS). Furthermore, the antimicrobial activity against S. aureus and E. coli biofilm formation was evaluated by fluorescence. The results indicate that AgNPs were adhered near the PDMS coating surface, assuring antimicrobial activity against the studied microorganisms at a concentration of about 0.04 μg cm−2 and average particle size of 170.5 nm. Therefore, the SBSp technique, used to produce PDMS/AgNPs coating in two steps, proved to be a suitable method to produce antimicrobial coatings with potential applications in active packaging and self-disinfecting surfaces.