Polymer Surfaces enhanced Raman effect

SPECTROSCOPY OF POLYMER SURFACES USING THE SURFACE ENHANCED RAMAN EFFECT... 

Raman scattering spectroelectrochemical investigations can be carried out for polymers deposited at practically any electrode used in electrochemical investigations (platinum, ITO, glassy carbon and others). In addition, successful application of SERS (surface enhanced Raman spectroscopy) for polypyrrole [124] and polythiophene [117] allows for Raman spectroscopic studies of extremely thin layers of conjugated polymers. Raman spectra of conjugated polymers are sometimes obscured by strong fluorescence. This problem can be effectively resolved by the... 

In addition to ordinary inelastic Raman scattering, two additional resonance enhancement forms of Raman spectroscopy have proven useful for the study of polymers UV resonance Raman spectroscopy and surface-enhanced Raman spectroscopy. These two resonance techniques use conventional instrumentation but exhibit useful enhancement effects. 

For trace analysis in fluids, some Raman sensors (try to) make use of the SERS effect to increase their sensitivity. While the basic sensor layout for SERS sensors is similar to non-enhanced Raman sensors, somehow the metal particles have to be added. Other than in the laboratory, where the necessary metal particles can be added as colloidal solution to the sample, for sensor applications the particles must be suitably immobilised. In most cases, this is achieved by depositing the metal particles onto the surfaces of the excitation waveguide or the interface window and covering them with a suitable protection layer. The additional layer is required as otherwise washout effects or chemical reactions between e.g. sulphur-compounds and the particles reduce the enhancement effect. Alternatively, it is also possible to disperse the metal particles in the layer material before coating and apply them in one step with the coating. Suitable protection or matrix materials for SERS substrates could be e.g. sol-gel layers or polymer coatings. In either... 

SERS offers considerable promise for the study of polymers for several reasons. The enhancement effect can increase Raman scattering by a factor of 10 -10 . Adsorption of molecules on the SERS-active metal surface causes fluorescence quenching in highly fluorescent compounds. In addition, surface-enhanced resonance Raman scattering can further enhance the Raman scattering efficiency by a factor of 10 -10 above that observed under resonance or surface-enhanced conditions alone. 

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