Smectic ordered structure and water repellency of a poly(fluoroalkyl acrylate) with a carbamate linker

Thermal behavior, molecular aggregation structure, and water repellency for poly{2-[(perfluorooctylethyl)carbamate]ethyl}acrylate (PFAUr-C 8 ) were studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM), wide-angle X-ray diffraction (WAXD), grazing-incidence wide-angle X-ray diffraction (GI-WAXD), contact angle measurements, and X-ray photoelectron spectroscopy (XPS). The impact of the carbamate linker was verified by comparison with poly[2-(perfluorooctyl)ethyl]acrylate (PFA-C 8 ). PFAUr-C 8 exhibited two phase transitions at 357 K and 416 K, whereas PFA-C 8 showed a single-phase transition at 347 K. Both PFAUr-C 8 and PFA-C 8 formed a bilayered hexatic smectic-B phase at room temperature. Although the lamellar structure for the fluoroalkyl ( R f ) groups was immediately lost in PFA-C 8 after disordering of the lateral translational order, PFAUr-C 8 maintained a stacked lamellar structure without lateral translational order. PFAUr-C 8 exhibited excellent water repellency at room temperature similar to PFA-C 8 . The outstanding thermal stability of the lamellar structure in PFAUr-C 8 is attributed to the cohesive interaction of the carbamate linkage.