Polymeric coatings with positive surface charge offer potential antimicrobial activity, which they owe to a simple electrostatic attraction with negatively charged bacterial walls and membranes. We describe synthesis and characterization of poly(2-aminoethyl methacrylate) and its copolymers with methyl methacrylate and butyl acrylate, as potential binders for antimicrobial solvent-cast paints. TiO2 and CaCO3 mineral particles were employed as model pigments/fillers, as they are used in most real-life paint formulations. Electrokinetic (ζ) potential and antimicrobial activity of thin films made of the (co)polymers in the absence and presence of TiO2 and CaCO3 nanopowders were assessed using streaming current measurements and microbial growth inhibition tests, respectively. Independently of the structure of the monomers used for the synthesis, the films showed positive ζ-potential values (up to +95 mV) in the pH range 3.5-8.0. The presence of mineral particles at 50% dry weight of the films did not affect significantly the ζ(pH) curves. The films made of the mixed dispersions remained positively charged and inhibited growth of both Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, as well as yeast (C. albicans). The mixed polymeric-mineral films described in this study seem to be promising potential candidates for designing antimicrobial coatings aimed to prevent spreading of bacterial infections.
Keywords: Antibacterial; Gram-negative; Gram-positive; Paint; Polymer; Titania.
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