Waterborne physically crosslinked antimicrobial nanogels

Supramolecular nanomaterials are formed by reversible connection of different building blocks; commonly non-covalent interactions lead to the formation of these materials. In this report, we present the preparation of very stable physically crosslinked nanogels (PCNGs) via a simple one pot reaction in water as solvent. Branched poly(ethylene imine) (PEI) is functionalized with C-10 alkyl chains and azetidinium groups yielding an amphiphilic polymer, which due to the hydrophobic interaction of the alkyl chains and the ionic repulsion of the azetidinium groups forms PCNGs with high colloidal stability. As the dynamic hydrophobic interactions are the main driving force in the formation of these nanogels, the PCNG show a temperature responsive behavior with respect to the zeta potential, particle size (hydrodynamic diameter), and polydispersity index. The potential of the PCNGs to form protective coatings is shown by the formation of ultrathin films on mica and highly oriented pyrolytic graphite. Finally the antimicrobial efficacy of the PCNGs was proven against a wide range of bacteria.