Atmospheric Plasma Deposition of Methacrylate Bio-Based Composite Coatings for Enhanced Release Function and Antimicrobial Properties of Paper

Paper based functional coatings are traditionally made from low recyclable synthetic feedstock and wet chemistry approaches, potentially associated to longer processing times and higher material consumption. In this work, we address these aspects with the development of functional bio-based high-performance composite coatings reinforced with sustainable fillers using atmospheric pressure plasma as sustainable oriented coating technology.<br/>Three different low viscosity acrylated Lignin based monomer, namely, Vanillyl Alcohol Methacrylate (VAM), Eugenyl Methacrylate (EM) and Isosorbide Methacrylate (IM), were used as resin, where seashell particles (SS), cellulose nanocrystals (CNC) as well as chitin from shrimp shell particles were used as sustainable additives. The methacrylation was obtained using methacrylic anhydride following an adopted procedure from <i>Stanzione et al</i>.<br/>The polymerization of these different monomers was possible thanks to a liquid assisted dielectric barrier discharge approach and was evidenced by FTIR showing a successful conversion of double bonds during the plasma polymerization. Coatings of a thickness ranging from 0.5 to 2 µm was deposited on Si wafers and Glassine paper using Ar or N₂ as plasma gas and ultrasonic nebulization as monomer injection method. The degree of conversion was calculated from the FTIR spectra to assess the effect of the plasma parameters on the polymerization and coating properties. SEM pictures showed homogeneous coating and a uniform distribution of the particles. It was confirmed that the polymerization degree increases with the applied plasma power and decreases with the monomer delivery rate. The addition of SS and CNC particles to the VAM or EM coating influences the hydrophobicity and surface energy and it is believed that this affect also the release properties of the coated surface. The best release function of coated Glassine paper was obtained with the VAM composite coating (&lt;250cN/25mm according to Finat 10/TESA 7475 test). The lower viscosity of VAM induces smaller droplets after ultrasonic nebulization and thus a better polymerization. The influence of particle addition on the physical properties of the composite coating was assessed by scratch test.<br/>In another hand, Chitin particles were used as antimicrobial additive and were embedded in IM to deposit a composite coating. The effect of chitin loading on the antimicrobial properties of the plasma composite coatings will be discussed.<br/><br/>References:<br/>J. F. Stanzione et al., ChemSusChem, 5, 1–8 (2012)