SERS of acrylic acid and methyl derivatives on silver sols

The surface-enhanced Raman scattering (SERS) spectra on silver colloids of acrylic acid and three methyl derivatives crotonic (3-methylacrylic), methacrylic (2-methylacrylic) and 3,3-dimethylacrylic acid, were recorded and analysed at different concentrations. At high concentrations the respective SERS spectra are explained as being due to the adsorption of the respective anionic forms via the π-ethylenic system or via the carboxylate group, except in the case acrylic acid, for which the presence of the propionate ion was also detected. The SERS of 3,3-dimethylacrylate is not affected by the concentration of the adsorbate, whereas for the remaining acids the SERS obtained at low concentration show the same spectrum as the saturated monocarboxylic acids in dilute conditions. © 1998 John Wiley & Sons, Ltd.