Anti‐microbial coatings by agent entrapment in coatings deposited via atmospheric pressure plasma liquid deposition

By injecting a liquid aerosol precursor directly into a non‐equilibrium atmospheric pressure plasma (APP), a controlled, free‐radical‐induced polymerisation reaction can be initiated with minimal fragmentation of the precursor molecules. This can be used to chemically graft highly complex chemical functionalities directly onto a variety of substrates. This process normally proceeds through polymerisation of unsaturated functional groups on the precursor molecules. In this work, it has been found that compounds that lack such polymerisable groups can be physically dissolved in the liquid precursor and that these chemicals are not directly involved in the plasma reaction. Instead, these chemicals become physically entrapped within the resultant plasma polymer and retain much of their biological and chemical properties. As a preliminary example of such a reaction, the entrapment of various anti‐microbial species (quaternary ammonium salts) within glycol and acrylic acid plasma polymers is described. The biological and chemical reactivity of these chemicals is examined using a combination of anti‐microbial and XPS investigations.