Temperature-Dependent Surface Enrichment Effects in Binary Mixtures of Fluorinated and Non-Fluorinated Ionic Liquids.

ABSTRACT: Using angle-resolved X-ray photoelectron spectroscopy (ARXPS), we investigate the topmost nanometers of various binary ionic liquid (IL) mixtures at different temperatures in the liquid state. The mixtures consist of ILs with the same [PF₆ ]^- anion but two different cations, namely 3-methyl-1-(3,3,4,4,4-pentafluorobutyl)imidazolium hexafluorophosphate, [PFBMIm][PF₆ ], and 1-butyl-3-methylimidazolium hexafluorophosphate, [C₄ C₁ Im][PF₆ ], with 10, 25, 50 and 75 mol % content of [PFBMIm][PF₆ ]. We observe a preferential enrichment of the fluorinated chain in the topmost layer, relative to the bulk composition, which is most pronounced for the lowest content of [PFBMIm][PF₆ ]. Upon cooling the mixtures ste

SUBMITTER: Heller BSJ 

PROVIDER: S-EPMC7027538 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature