title: Chemically transformable configurations of mercaptohexadecanoic acid self-assembled monolayers adsorbed on Au(111).
abstract: Carboxyl-terminated self-assembled monolayers (SAMs) are commonly used in a variety of applications, with the assumption that the molecules form well-ordered monolayers. In this work, near-edge X-ray absorption fine structure measurements verify that well-ordered monolayers can be formed using acetic acid in the solvent. Disordered monolayers with unbound molecules present in the film result using only ethanol. A stark reorientation occurs upon deprotonation of the end group by rinsing in a KOH solution. This reorientation of the end group is reversible with tilted-over, hydrogen-bound carboxyl groups while the carboxylate ion end groups are upright. C(1s) photoemission shows that SAMs formed and rinsed with acetic acid in ethanol have protonated end groups, while SAMs formed without acetic acid have a large fraction of carboxylate-terminated molecules.
authors.affiliation: Department of Physics, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
authors.forename: Trevor M
authors.initials: TM
authors.lastname: Willey
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Vance
authors.forename: T
authors.initials: T
authors.lastname: van Buuren
authors.forename: C
authors.initials: C
authors.lastname: Bostedt
authors.forename: A J
authors.initials: AJ
authors.lastname: Nelson
authors.forename: L J
authors.initials: LJ
authors.lastname: Terminello
authors.forename: C S
authors.initials: CS
authors.lastname: Fadley
mesh_terms: D000085:Acetates / Q000737:chemistry; D000327:Adsorption; D000431:Ethanol / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D010169:Palmitic Acids / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014965:X-Rays
chemical_list: C450319:16-mercaptohexadecanoic acid; D000085:Acetates; D010169:Palmitic Acids; D000431:Ethanol; D006046:Gold