title: Adlayers of dimannoside thiols on gold: surface chemical analysis.
abstract: Carbohydrate films on gold based on dimannoside thiols (DMT) were prepared, and a complementary surface chemical analysis was performed in detail by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), near-edge X-ray absorption fine structure (NEXAFS), FT-IR, and contact angle measurements in order to verify formation of ω-carbohydrate-functionalized alkylthiol films. XPS (C 1s, O 1s, and S 2p) reveals information on carbohydrate specific alkoxy (C-O) and acetal moieties (O-C-O) as well as thiolate species attached to gold. Angle-resolved synchrotron XPS was used for chemical speciation at ultimate surface sensitivity. Angle-resolved XPS analysis suggests the presence of an excess top layer composed of unbound sulfur components combined with alkyl moieties. Further support for DMT attachment on Au is given by ToF-SIMS and FT-IR analysis. Carbon and oxygen K-edge NEXAFS spectra were interpreted by applying the building block model supported by comparison to data of 1-undecanethiol, poly(vinyl alcohol), and polyoxymethylene. No linear dichroism effect was observed in the angle-resolved C K-edge NEXAFS.
authors.affiliation: Surface and Thin Film Analysis WG, BAM Federal Institute for Materials Research and Testing, D-12203 Berlin, Germany. Paul.Dietrich@BAM.de
authors.forename: Paul M
authors.initials: PM
authors.lastname: Dietrich
authors.forename: Tim
authors.initials: T
authors.lastname: Horlacher
authors.forename: Pierre-Luc
authors.initials: PL
authors.lastname: Girard-Lauriault
authors.forename: Thomas
authors.initials: T
authors.lastname: Gross
authors.forename: Andreas
authors.initials: A
authors.lastname: Lippitz
authors.forename: Hyegeun
authors.initials: H
authors.lastname: Min
authors.forename: Thomas
authors.initials: T
authors.lastname: Wirth
authors.forename: Riccardo
authors.initials: R
authors.lastname: Castelli
authors.forename: Peter H
authors.initials: PH
authors.lastname: Seeberger
authors.forename: Wolfgang E S
authors.initials: WE
authors.lastname: Unger
mesh_terms: D004187:Disaccharides / Q000737:chemistry*; D006046:Gold; D008362:Mannosides / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D004187:Disaccharides; D008362:Mannosides; D013438:Sulfhydryl Compounds; D006046:Gold