The present invention relates to methods for forming antimicrobial coatings, and to compounds suitable for forming the antimicrobial coatings, and to substrates coated with the antimicrobial coatings. The coatings are formed by vapour phase plasma polymerisation of metal ion complexes each having at least one polymerisable ligand, which includes a polymerisable moiety such as a C—C double bond or a C—C triple bond.
