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Polymers The TOF-SIMS spectra obtained from polymer surfaces can be divided into three different regions. Oligomer Region I In this high mass range (up to 10,000 u) intact oligomer ions can be observed. These quasimolecular ions are typically formed by an attachment (M+H) or loss of a hydrogen (M-H) . In addition to this cationisation by the attachment of a substrate ions or alkaline ion can be observed. Fragment Region II Here, typically ions consisting of multiple repeat units with and without the loss of functionalgroups are observed. The formation of these ions follows "classical" fragmentation rules. Fingerprint Region III In this low mass range (up to 300 u) ions consisting of end groups, fractions of repeat units, or side chains are observed. In general the detection of these low mass fragments is sufficient for an identification of the polymer.   Polymer Additives As an example for imaging of organic materials the image of the polymer additive, Tinuvin 770, in LDPE (low density polyethylene) is shown. The high concentration of the additive in the polymer matrix leads to blooming at the surface. |
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Fingerprint Ions of Polycarbonate Static SIMS spectrum obtained from polystyrene prepared on an etched silver substrate.  Tinuvin 770 |