Low critical surface energies of novel fluorinated poly(amide urethane) block copolymers were measured. The copolymers contain a "hard block" polyurethane consisting of a diisocyanate and a diol and a "soft block" non-self-associating polyamide consisting of oligomers synthesized from fluorinated secondary diamines and adipoyl chloride. The various diisocyanates studied were methylenebis(phenylene isocyanate) (MDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), and methylenebis-(cyclohexane isocyanate) (H12MDI). Butanediol and hexanediol were the diols used. The different diamines studied were N//'-diisopropyl-l,6-diaminohexane, iV^V'-bis(2,2,2-trifluoroethyl)-l,6-diaminohexane-1,6-diaminohexane, V,V'-bis(3,3,3,2,2-pentafluoropropyl)-l,6-diaminohexane, IV,JV'-bis(Iff,lffheptafluorobutyl)-l,6-diaminohexane, and NJf'-bis( 1H,l//-perfluorooctyl)-l,6-diaminohexane. The critical surface tensions of the poly( amide urethane) block copolymers were determined with Zisman plots using contact angle goniometry, and water contact angles were obtained by both goniometry and the Wilhelmy method. Intrinsic viscosities and thermal transitions were determined. The large hysteresis seen in the contact angle measurements and the kinetic instability of water drop shapes on polymer films indicate that although the air-polymer interface shows a fluorinated surface, exposure to water can effect a rearrangement allowing exposure of a more polar entity.
