Organic film analysis using SIMS

This method has traditionally been used for the elemental analysis of surfaces ("dynamic" SIMS). Organic materials can be subjected to SIMS, too, by depositing them as a thin film on a metal (or other) foil, occasionally together with a salt. The sample is bombarded by a primary ion beam (e.g., Ar or Cs ), which leads to the sputtering of secondary ions from the surface. The latter can be M, M , [M -i- Ag] (if a silver surface is used), or [M -i- alkali] ... 

The plateau of the adsorption isotherm indicates the concentration(s) at which all adsorption sites for the adsorbing species are occupied, in surface chemistry terms the fractional surface coverage of the substrate by the adsorbate is unity. Such a specimen provides an ideal opportunity to probe the interfecial chemistry of adhesion directly using what is sometimes referred to as the thin film approach. As the layer of organic material, such as adhesive, is very thin (as a result of monolayer coverage) the contribution of interfacial chemistry at the interface will be maximized in the resultant XPS or ToF-SIMS spectrum. For this reason, the construction of adsorption isotherms is often used as a precursor to direct interphase analysis in this manner. 

---