UV-Vis Reflection-Absorption Spectroscopy at air-liquid interfaces

Carlos Rubia-Payá; Gustavo de Miguel; María T Martín-Romero; Juan J Giner-Casares; Luis Camacho

doi:10.1016/j.cis.2015.08.012

UV-Vis Reflection-Absorption Spectroscopy at air-liquid interfaces

Adv Colloid Interface Sci. 2015 Nov:225:134-45. doi: 10.1016/j.cis.2015.08.012. Epub 2015 Sep 3.

Authors

Carlos Rubia-Payá¹, Gustavo de Miguel¹, María T Martín-Romero¹, Juan J Giner-Casares², Luis Camacho³

Affiliations

¹ Institute of Fine Chemistry and Nanochemistry, Department of Physical Chemistry and Applied Thermodynamics, University of Córdoba, Campus Universitario de Rabanales, Edificio Marie Curie, Córdoba, E-14014, Spain.
² Institute of Fine Chemistry and Nanochemistry, Department of Physical Chemistry and Applied Thermodynamics, University of Córdoba, Campus Universitario de Rabanales, Edificio Marie Curie, Córdoba, E-14014, Spain. Electronic address: jjginer@uco.es.
³ Institute of Fine Chemistry and Nanochemistry, Department of Physical Chemistry and Applied Thermodynamics, University of Córdoba, Campus Universitario de Rabanales, Edificio Marie Curie, Córdoba, E-14014, Spain. Electronic address: lcamacho@uco.es.

PMID: 26385430
DOI: 10.1016/j.cis.2015.08.012

Abstract

UV-Visible Reflection-Absorption Spectroscopy (UVRAS) technique is reviewed with a general perspective on fundamental and applications. UVRAS is formally identical to IR Reflection-Absorption Spectroscopy (IRRAS), and therefore, the methodology developed for this IR technique can be applied in the UV-visible region. UVRAS can be applied to air-solid, air-liquid or liquid-liquid interfaces. This review focuses on the use of UVRAS for studying Langmuir monolayers. We introduce the theoretical framework for a successful understanding of the UVRAS data, and we illustrate the usage of this data treatment to a previous study from our group comprising an amphiphilic porphyrin. For ultrathin films with a thickness of few nm, UVRAS produces positive or negative bands when p-polarized radiation is used, depending on the incidence angle and the orientation of dipole absorption. UVRAS technique provides highly valuable information on tilt of chromophores at the air-liquid interface, and moreover allows the determination of optical parameters. We propose UVRAS as a powerful technique to investigate the in situ optical properties of Langmuir monolayers.

Keywords: Aggregation; Chromophores; Interfaces; Langmuir monolayers; Reflection spectroscopy; Self-assembly.

Publication types

Review