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Hydroxy-terminated poly(2,2-substituted-1,3-propylene oxide) telechelics and co-telechelics bearing semifluorinated (R = -CH(2)OCH(2)(CF(2))(n)CF(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(3FOx-BrOx) have higher theta(adv) and lower theta(rec) than the homo-telechelic PUs [P(3FOx) = poly(2-methyl-2-trifluoroethoxymethyl-1,3-propylene oxide; P(BrOx) = poly(2-methyl-2-bromomethyl-1,3-propylene oxide)]. For IPDI-BD(40)/P(3FOx/BrOx-1:1), theta(adv) (116 degrees) is higher and theta(rec) (32 degrees) is lower (Deltatheta, 84 degrees ) 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.

The sensitized photoracemization of a number of alkyl aryl sulfoxides, la-f, has been shown to depend on transfer of energy from the excited singlet state of naphthalene. Exothermic electronic energy transfer is ruled out. A mechanism requiring exciplex formation and subsequent radiationless decay is proposed. Substitution of the substrate shows that steric and electronic effects on the rates of fluorescence quenching or of photoracemization are small.

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