Polyurethanes containing oxetane-derived poly(2,2-substituted-1, 3-propylene oxide) soft blocks: Copolymer effect on wetting behavior

Hydroxy-terminated poly(2,2-substituted-1,3-propylene oxide) telechelics and co-telechelics bearing semifluorinated (R = -CH 2OCH 2(CF 2) nCF 3, n = 0,1) and/or bromomethyl pendant groups were synthesized from the corresponding 3,3-substituted oxetanes. The new telechelics were incorporated in polyurethanes (PUs) with isophorone diisocyanate (IPDI) and 1,4-butanediol (BD) as the hard block. Surface properties were evaluated using tapping mode atomic force microscopy (TM-AFM) and dynamic contact angle (DCA) analysis. Interestingly, polyurethanes containing P(SFOx-BrOx) have higher θ adv and lower θ rec than the homo-telechelic PUs [P(3FOx) = poly(2-methyl-2-trifluoroethoxymethyl-l,3-propylene oxide; P(BrOx) = poly(2-methyl-2-bromomethyl-1,3-propylene oxide)]. For IPDI-BD(40)/P(3FOx/BrOx-1:1), θ adv (116°) is higher and θ rec (32°) is lower (Δθ, 84°) than any other homo- or co-telechelic polyurethane. The unusual wetting behavior for P(FOx/BrOx) polyurethanes is correlated with FOx-BrOx dyad content, and a reversible H-bonding mechanism is proposed to explain the results. © 2005 American Chemical Society