Partially hydrolyzed poly(2-​oxazoline)​s and poly(2-​oxazine)​s as additives for the preparation of self-​disinfectant surfaces

The usage of antimicrobially active polymers as additives in commodity materials enables the preparation of self-disinfectant surfaces for sanitary applications. Based on a study of the use of partially hydrolyzed poly(2-oxazoline)s as contact biocides [1], novel antimicrobially active polymers have been developed, namely partially hydrolyzed poly(2-oxazoline)s and poly(2-oxazine) with reduced water solubility. Cell membrane potential assays showed that non-hydrolyzed poly(2-nonyl-2-oxazoline) could not cause cell damage in E. coli strains. Poly(2-nonyl-2-oxazoline)s with hydrolysis degrees of 80 and 100%, however, killed about 50/80% of E. coli.

For the reduction of the water solubility of the polymer-based biocides, two approaches have been pursued, the synthesis and partial hydrolysis of higher homologues of poly(2-oxazoline)s, in particular poly(2-oxazine)s, as well as crosslinking of copoly(2-oxazoline)s by means of the UV-induced thiol-ene reaction [2]. Various poly(2-oxazoline)s and poly(2-oxazine)s with hydrolysis degrees of 0 and 50% were tested as 2.5 wt.-% additive in polypropylem compounds against the four germs E. coli, S. aureus, P. aeruginosa, and C. albicans.

The surfaces of compounds with partially hydrolyzed poly(2-phenyl-2-oxazine) exhibited high antimicrobial acticity against all four germs (Figure 1). With the exception of P. aeruginosa, also partially hydrolyzed poly(2-phenyl-2-oxazoline) proved to be an antimicrobially active additive; nonetheless, partially hydrolyzed poly(2-phenyl-2-oxazine) always showed a more pronounced antimicrobial action.