title: Competitive adsorption on graphite investigated using frequency-modulation atomic force microscopy: interfacial liquid structure controlled by the competition of adsorbed species.
abstract: The competitive adsorption of long-chain (C18 and C24) carboxylic acids versus n-decanol on graphite was investigated using frequency-modulation atomic force microscopy. A long-range-ordered monolayer of the solute (stearic acid or lignoceric acid) developed in saturated decanol solution, whereas an ordered decanol monolayer was deposited from dilute solutions. The piconewton-order tip-surface force was observed in solutions as a function of the vertical and lateral coordinates, together with the topography of the monolayers. The tip-surface force was periodically modulated, which was interpreted with a solution structure commensurate with the ordered assembly of adsorbed monolayers. These results show that the solution structure at the interface was controlled by the competitively adsorbed species and thus was sensitive to the composition of the bulk solution.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University, Nada, Kobe 657-8501, Japan. hiasa@people.kobe-u.ac.jp
authors.forename: Takumi
authors.initials: T
authors.lastname: Hiasa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Onishi
mesh_terms: D000327:Adsorption; D002264:Carboxylic Acids / Q000737:chemistry*; D005233:Fatty Alcohols / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D010316:Particle Size; D013499:Surface Properties
chemical_list: D002264:Carboxylic Acids; D005233:Fatty Alcohols; D006108:Graphite; C029383:n-decyl alcohol