Metal-oxide aqueous interfaces are important in areas as varied as photocatalysis and mineral reforming. Crucial to the chemistry at these interfaces is the structure of the electrical double layer formed when anions or cations compensate for the charge arising from adsorbed H or OH. This has proven extremely challenging to determine at the atomic level.
View Article and Find Full Text PDFOptimization of boundary lubrication by tuning the confined molecular structures formed by surface-active additives such as surfactants and polymers is of key importance to improving energy efficiency in mechanical processes. Here, using the surface forces apparatus (SFA), we have directly measured the normal and shear forces between surface layers of a functionalised olefin copolymer (FOCP) in n-dodecane, deposited onto mica using the Langmuir-Blodgett (LB) technique. The FOCP has an olefin backbone decorated with a statistical distribution of polar-aromatic groups, with a structure that we term as "centipede".
View Article and Find Full Text PDFWe report the morphology and microstructure of -dialkyl side-chain-substituted thiophene DPP end-capped with phenyl groups (Ph-TDPP-Ph) thin films and compare the influence of deposition method and substrate surface using thermally oxidized Si and graphene substrates as well as monolayer graphene surfaces with an underlying self-assembled octadecyltrichlorosilane monolayer, complemented by an aging study of spin-coated films over a 2 weeks aging period. A distinct difference in morphology was observed between spin-coated and vacuum-deposited thin films, which formed a fiber-like morphology and a continuous layer of terraced grains, respectively. After an initial film evolution, all combinations of deposition method and substrate type result in well-ordered thin films with almost identical crystalline phases with slight variations in crystallinity and mosaicity.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2021
Controlling corrosion with naturally occurring corrosion scales is potentially a more environmentally sustainable alternative to current approaches, including dosing of organic corrosion inhibitors. We report grazing incidence X-ray diffractograms correlated with electrochemical measurements to elucidate the growth and corrosion protection properties of a corrosion scale composed of FeCO crystallites, which is encountered in various key energy industry applications. Data, acquired as a function of time from high-purity iron immersed in CO-saturated deionized HO at pH 6.
View Article and Find Full Text PDFJ Synchrotron Radiat
March 2021
Compton scattering is generally neglected in diffraction experiments because the incoherent radiation it generates does not give rise to interference effects and therefore is negligible at Bragg peaks. However, as the scattering volume is reduced, the difference between the Rayleigh (coherent) and Compton (incoherent) contributions at Bragg peaks diminishes and the incoherent part may become substantial. The consequences can be significant for coherent diffraction imaging at high scattering angles: the incoherent radiation produces background that smears out the secondary interference fringes, affecting thus the achievable resolution of the technique.
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