309 research outputs found
Water modulates the lamellar structure and interlayer correlation of poly(perfluorooctyl acrylate) films: a specular and off-specular neutron scattering study
Comb-like polymers with pendant-like perfluorocarbon side chains self-assemble into smectic lamellae and have been extensively used as water-repellent, hydrophobic coating materials characterized by large water contact angles (θ > 120°). As poly(perfluorooctyl acrylate) films are “apparently hydrophobic” (θ > 120°), the interaction of such materials and water molecules has been largely overlooked. To unravel the molecular-level interactions between water and apparently hydrophobic polymers, specular and off-specular neutron scattering experiments were conducted at defined osmotic pressure ΠH2O. The poly{2-[(perfluorooctylethyl)carbamate]ethyl} acrylate (PFAUr-C₈), which had a carbamate linker, transitioned to another lamellar phase at 89 °C. At T = 25 °C; the lamellar periodicity of PFAUr-C₈ slightly increased with decreasing osmotic pressure, while the vertical correlation length increased. However, the poly[(perfluorooctyl)ethyl] acrylate (PFA-C₈) that did not contain a carbamate linker directly transitioned to a disordered phase at 84 °C. The lamellar periodicity of PFA-C₈ was largely independent of the osmotic pressure, suggesting that PFA-C₈ was poorly hydrated. Remarkably, the vertical correlation length decreased with decreasing osmotic pressure. 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
Large-scale self-assembled zirconium phosphate smectic layers via a simple spray-coating process
Shear flow orientation of thermotropic liquid crystals of rigid-rod polyesters with flexible side chains
In situ ultra-small-angle X-ray scattering study under uniaxial stretching of colloidal crystals prepared by silica nanoparticles bearing hydrogen-bonding polymer grafts
Analysis of spatial orientation distribution of highly oriented polyimide film using micro ATR-FTIR spectroscopic imaging method
Quantitative analysis of stereoscopic molecular orientations in thermally reactive and heterogeneous noncrystalline thin films via variable-temperature infrared pMAIRS and GI-XRD
Evaluation of thermal diffusivity of cross-linked liquid crystalline polyimides with siloxane units
Crystallization-induced structure fluctuation of crystallized microdomain structure composed of strongly segregated crystalline-crystalline diblock copolymers
Ultrafast spectroscopic analysis of pressure-induced variations of excited-state energy and intramolecular proton transfer in semi- aliphatic polyimide films
- …