2381/11806449.v1 Katharina Haeckl Katharina Haeckl Hua Li Hua Li Iain M Aldous Iain M Aldous Terrence Tsui Terrence Tsui Werner Kunz Werner Kunz Andrew P Abbott Andrew P Abbott Gregory G Warr Gregory G Warr Rob Atkin Rob Atkin Potential Dependence of Surfactant Adsorption at the Graphite Electrode/Deep Eutectic Solvent Interface University of Leicester 2020 Science & Technology Physical Sciences Technology Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Atomic, Molecular & Chemical Chemistry Science & Technology - Other Topics Materials Science Physics SHAPE-CONTROLLED SYNTHESIS ALKYL CHAIN-LENGTH IONIC LIQUIDS DOUBLE-LAYER FORCE MICROSCOPY ELECTRODEPOSITION NANOSTRUCTURE MIXTURES NICKEL MICA 2020-02-26 16:31:18 Journal contribution https://figshare.le.ac.uk/articles/journal_contribution/Potential_Dependence_of_Surfactant_Adsorption_at_the_Graphite_Electrode_Deep_Eutectic_Solvent_Interface/11806449 Copyright © 2019 American Chemical Society. Atomic force microscopy and cyclic voltammetry are used to probe how ionic surfactant adsorbed layer structure affects redox processes at deep eutectic solvent (DES)/graphite interfaces. Unlike its behavior in water, sodium dodecyl sulfate (SDS) in DESs only adsorbs as a complete layer of hemicylindrical hemimicelles far above its critical micelle concentration (CMC). Near the CMC it forms a tail-to-tail monolayer at open-circuit potential (OCP) and positive potentials, and it desorbs at negative potentials. In contrast, cetyltrimethylammonium bromide (CTAB) adsorbs as hemimicelles at low concentrations and remains adsorbed at both positive and negative potentials. The SDS horizontal monolayer has little overall effect on redox processes at the graphite interface, but hemimicelles form an effective and stable barrier. The stronger solvophobic interactions between the C16 versus C12 alkyl chains in the DES allow CTAB to self-assemble into a robust coating at low concentrations and illustrate how the structure of the DES/electrode interface and electrochemical response can be engineered by controlling surfactant structure.