Influence of Satellite Groups on Telechelic Antimicrobial Functions of Polyoxazolines

The antimicrobial activity of poly(alkyloxazoline) telechelics with one quaternary N,N‐dimethyldodecylammonium (DDA) end group was found to be greatly controlled by the non‐bioactive distal end group, the so‐called satellite group. In systematic investigations, the nature of the latter groups was varied to explore the mechanism of the satellite effect. To this end, poly(2‐alkyl‐1,3‐oxazoline)s (alkyl = ethyl, methyl) with a DDA‐group at the terminating end and varying alkyl, aminoalkyl, and polyphenyloxazoline block satellite groups, have been synthesized. Poly(oxazoline) derivatives with polydispersity indices of 1.06–1.20 and molecular weights from 2 200 to 12 800 g · mol−1 could be obtained. The macromolecular structures have been confirmed by NMR spectroscopy and ESI‐MS measurements. The polymers were investigated with regard to their antibacterial efficiency towards the Gram‐positive bacterium Staphylococcus aureus and the Gram‐negative bacterium Escherichia coli. It was found that the introduction of alkyl chain satellites of 4–10 carbon atoms in length afforded antimicrobial activity of the polymers against both microbes that was about 2–3 times higher than that of the well‐known structurally comparable low molecular weight biocide, dodecyltrimethylammonium chloride (DTAC). Based on the antimicrobial effects of the investigated polymers, a mechanism for the satellite effect was proposed.