Sustainable antimicrobial and antibiofilm strategies: Monoterpene-based compounds as potential substitute for low-molecular-weight biocides in the coating industry

• Promising potential of terpene acrylates as substitutes for commercial biocides. • Polarity of terpenes and related monomers influences the antimicrobial activity. • Sustained biocidal activity in polymer form: 100 % biofilm prevention achieved by using thymol acrylate. • Antibiofilm properties can be controlled by concentration and proportion of terpene acrylates in the copolymer. Biocides are commonly used to protect against microbiological contamination but are typically toxic and pose significant environmental risks. This study explores the development of sustainable, environmentally friendly alternatives to conventional biocides for protecting water-based coating systems. We investigated natural antibacterial agents, particularly monoterpenes, to develop antimicrobial acrylate monomers and assess whether their efficacy is maintained in polymer form. Acrylate monomers derived from limonene, its oxidation products, and thymol were evaluated for their potential as biocide substitutes in aqueous media and as biofilm-resistant polymers. Our findings indicate that polymerizing terpene acrylates can prevent the leaching of antimicrobial agents while preserving their effectiveness. We analyzed the antimicrobial activity of various acrylate monomers with different polarities, as well as the biofilm formation properties of the resulting polymers. Additionally, we examined the copolymerization of these monomers with methyl methacrylate to assess the antibacterial and biofilm-inhibitory properties of the copolymers. Limonene-based acrylates (LA, LOA, and LHA) significantly suppressed bacterial growth, while TyA (thymol acrylate) completely inhibited it. Polymers derived from these acrylates exhibited reduced biofilm formation, with thymol acrylate-based polymers achieving complete biofilm prevention and a logarithmic reduction of > 6 for both the homopolymer and copolymer. These results suggest that these functional monomers and polymers offer a promising approach to replacing toxic biocides in coating systems, providing sustained antimicrobial resistance while minimizing environmental impact.