2022 Volume 32 Issue 3 Pages 128-132
The structures of “apparently hydrophobic” poly(perfluorooctyl acrylate) films composed of acrylate polymers with pendant-like perfluorocarbon side chains connected by different linkers were investigated using off-specular neutron scattering experiments at defined osmotic pressure. The poly[(perfluorooctyl)ethyl] acrylate (PFA-C8) showed almost identical lamellar periodicity independent of the osmotic pressure, suggesting that PFA-C8 was poorly hydrated. The poly{2-[(perfluorooctylethyl) carbamate]ethyl} acrylate (PFAUr-C8) showed the slight increase of the lamellar periodicity with decreasing osmotic pressure, while the vertical correlation length increased. These films showed different thermotropic transitions under hydration; PFA-C8 directly transitioned to a disordered phase at 84 °C, while PFAUr-C8 transitioned to another lamellar phase at 89 °C. Because hydration facilitated by the linker modulated the smectic lamellae of the poly(perfluoroalkyl acrylate), water molecules could be used to optimize the self-assembly of apparently hydrophobic liquid crystalline polymers.
