Corrugated Ionic Liquid Surfaces with Embedded Polymer Stabilized Platinum Nanoparticles

Ionic liquids such as 1-butyl-2,3-dimethyl-imidazolium trifluoromethane sulfonate stabilize complex structures of polyvinylpyrrolidone protected nanoparticles on their surface. The polyvinylpyrrolidone shell around the Pt nanoparticles remains intact, but the ionic liquid partly penetrates the protective layer and interacts with the metal. This leads to a pronounced increase of the viscosity of the ionic liquid, as observed also with metal complexes. The protected particles form small islands of aggregated moieties that are connected by interacting polymer strands, a process enhanced by diluting the sample in methanol during preparation. Some of these ensembles segregate at the surface protruding significantly out from the bulk ionic liquid. The outermost layer of the surface, however, consists of the ionic liquid with the cation being on top and the SO3 group of the anion underneath being oriented toward the bulk.