title: The Role of a Double Molecular Anchor on the Mobility and Self-Assembly of Thiols on Au(111): The Case of Mercaptobenzoic Acid.
abstract: The dynamics of the self-assembly process of thiol molecules on Au(111) is affected by the interplay between molecule-substrate and molecule-molecule interactions. Therefore, it is interesting to explore the effect of a second anchor to the gold surface, in addition to the S atom, on both the order and the feasibility of phase transitions in self-assembled monolayers. To assess the role of an additional O anchor, we have compared the adsorption of two mercaptobenzoic acid isomers, 2-mercaptobenzoic acid (2-MBA) and 4-mercaptobenzoic acid (4-MBA), on Au(111). Results from scanning tunneling microscopy, X-ray photoelectron spectroscopy, electrochemical techniques, and density functional theory calculations show that the additional O anchor in 2-MBA hinders surface mobility, reducing domain size and impeding the molecular reorganization involved in phase transition to denser phases on the Au(111) substrates. This knowledge can help to predict the range order and molecular density of the thiol SAM depending on the chemical structure of the adsorbate.
authors.affiliation: Área de Química Física, Departamento de Química, Facultad de Ciencias, Universidad de La Laguna, Instituto de Materiales y Nanotecnología, 38200-, La Laguna, Tenerife, Spain.
authors.forename: Miriam C
authors.initials: MC
authors.lastname: Rodríguez González
authors.affiliation: Área de Química Física, Departamento de Química, Facultad de Ciencias, Universidad de La Laguna, Instituto de Materiales y Nanotecnología, 38200-, La Laguna, Tenerife, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Carro
authors.affiliation: Instituto de Investigaciones Fisicoquímicas, Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET- Sucursal 4, Casilla de Correo 16, 1900, La Plata, Argentina.|Current Address: EP Imperial College London, Department of Chemistry, Exhibition Road, London, SW7 2AZ, UK.
authors.forename: Evangelina
authors.initials: E
authors.lastname: Pensa
authors.affiliation: Instituto de Investigaciones Fisicoquímicas, Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET- Sucursal 4, Casilla de Correo 16, 1900, La Plata, Argentina.
authors.forename: Carolina
authors.initials: C
authors.lastname: Vericat
authors.affiliation: Instituto de Investigaciones Fisicoquímicas, Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET- Sucursal 4, Casilla de Correo 16, 1900, La Plata, Argentina.
authors.forename: Roberto
authors.initials: R
authors.lastname: Salvarezza
authors.affiliation: Área de Química Física, Departamento de Química, Facultad de Ciencias, Universidad de La Laguna, Instituto de Materiales y Nanotecnología, 38200-, La Laguna, Tenerife, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Hernández Creus
keywords: density functional calculations; molecular dynamics; self-assembly; surface analysis; thin films