Positive secondary ion mass spectrum of poly(methyl methacrylate): a high mass resolution ToF-SIMS study

The positive SIMS spectrum of poly(methyl methacrylate) (PMMA) has been obtained with a mass resolution in excess of 8000 and all the components assigned up to m/z 200 based on accurate mass measurements. Aspects of the interpretation of the spectrum, previously based on quadrupole SIMS data from a number of acrylic polymers, need to be revised significantly. In particular, the spectrum is dominated by oxygen-containing fragments derived from oligomeric units rather than hydrocarbon fragments derived from the polymer backbone. To aid further the understanding of the fragmentation of acrylic polymers, a less-detailed study of poly(methyl acrylate) has also been carried out.