The effect of converting ammonium into guanidine moieties, compared to other factors such as molecular weight or hydrophobicity, on the antibacterial activity is investigated for homo‐ and copolymers of 2‐aminoethylmethacrylate in solution or coatings. Polymers are obtained by free radical polymerization, polymer‐analogous guanidinylation is conducted with cyanamide; non‐leaching immobilization is achieved by LBL assembly of homopolymers or crosslinking of functional sidegroups in copolymers. Antibacterial activity to Escherichia coli or Bacillus subtilis is determined by different standard methods. Guanidinylation improves antibacterial activity and speed as well as cytotoxicity of hydrophilic homo‐ and copolymers in solution or coatings.
