Polyoxetane and Poly(co-oxetanes): Unexpected and Unprecedented Surface Science

Polyoxetanes are polyethers or formally 2,2-substituted-1,3-propylene oxides. Polyoxetane telechelics 1 may be represented as P[AB], where A and B are repeat units with differing side chains. These telechelics are incorporated into polyurethanes and used as polymer surface modifiers (Figure 1). An example is polyurethanes with P[AB] soft blocks where A = a semifluorinated chaperone or PEG-like side chain and B = alkylammonium side chains. At 2wt% in a conventional polyurethane, two of the surface modifiers effect 100% kill of a 107 CFU/ml aerosol challenge of Gram +/- pathogenic bacteria in 30 min. The effectiveness of the new modifiers is due in part to surface nano-topology and spatial distribution of alkylammonium groups mimicking naturally occurring biocidal peptides such as the magainins and cecropins.

Other copolyoxetane surface science will be presented including (a) novel contraphilic wetting (wet surface hydrophobic; dry surface hydrophilic) and (b) a semicrystalline polyoxetane (1, A = B = CF3CH2OCH2-) that spontaneously develops a topologically complex surface which becomes more hydrophobic (106°®140°) with time.

* The author thanks the National Science Foundation, Division of Materials Research for support of this research.