화학공학소재연구정보센터
Polymer, Vol.172, 312-321, 2019
Hydrophobicity enhancement of polyurethanes by attaching fluorinated end blocks via ATRP and correlation between surface properties and self-assembly nature
Hydrophobicity enhancement for polyurethane (PU) materials is important to explore new application range of PUs. We here prepare the triblock copolymer series with a PU middle block and fluorinated end blocks, poly (2,2,2-trifluoroethyl methacrylate) (PTFEMA), with various PTFEMA volume fraction (phi(PTFEMA)) at the range of 0.03 <= phi(PTFEMA )<= 0.60 by utilizing ATRP technique. Static contact angle tests demonstrate that the triblock copolymer with phi(PTFEMA) of 0.03 already attained much higher value of water contact angle (similar to 95 degrees) than the value (similar to 74 degrees) of PU homopolymer. The surface free energy (gamma) estimated by Owens-Wendt method was 48 mJ/m(2) for PU homopolymer while the value for triblock copolymer with phi(PTFEMA)= 0.16 attained a similar value (25 mJ/m(2)) to that of homo PTFEMA (24 mJ/m(2)). This reveals that the surface is mostly covered with fluorinated segments when phi(PTFEMA )>=( )0.16, which is supported by XPS analysis. We found from SAXS data that these surface property changes were fully correlated with the changes of self-assembly nature of copolymers depending on the length of PTFEMA end blocks.