D.Phil. Student, University of Oxford, 1999–2003
Vibrational Spectroscopy of Thin Organic Films
The use of vibrational spectroscopy for the study of thin organic films at interfaces was explored. Three different types of vibrational spectroscopy were considered: FTIR SPECTROSCOPY (FTIRS), unenhanced RAMAN SPECTROSCOPY and SUM-FREQUENCY SPECTROSCOPY. The advantages and limitations of each technique have been assessed for thin films at a variety of interfaces by means of an up to date literature survey and technical appraisal. Experiments were performed to aid comparison and to extend techniques to new and complex systems. The thin films were composed of laminated polymer coatings, cuticular wax layers on leaf surfaces in vivo, and single- or mutli-component surfactant films at the silica–water and air–water interfaces. The potential of vibrational spectroscopy to study surfactant films at the interface between water and an organic crystal was also experimentally assessed. The complementary techniques of vibrational spectroscopy were shown to be valuable for the characterisation of interfaces at the molecular-level.
A strong theme throughout this research was the development and application of total internal reflection (TIR)-Raman techniques, which have not been fully exploited to date. Unenhanced Raman spectra of very high quality are presented from a range of films at interfaces, with thicknesses down to 2–3 nm. TIR-Raman spectroscopy is shown to have ample sensitivity for monolayer studies, even without resonant or surface enhancement.
P. R. Greene and C. D. Bain "Total Internal Reflection Raman Spectroscopy of Barley Leaf Epicuticular Waxes In Vivo" Colloids and Surfaces, B: Biointerfaces 2005, 45, 174–180 (DOI).
P. R. Greene and C. D. Bain "Total Internal Reflection Raman Spectroscopy" Spectroscopy Europe 2004, 16, 8–15.
C. D. Bain and P. R. Greene "Spectroscopy of Adsorbed Layers" Current Opinion in Colloid & Interface Science 2001, 6, 313–320 (DOI).