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Static SIMS spectra of polystyrene obtained by ‘living’ radical polymerization. Part II: Molecular weight quantification based on end groups
Author(s) -
Vanden Eynde X.,
Bertrand P.
Publication year - 1998
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/(sici)1096-9918(199807)26:8<579::aid-sia404>3.0.co;2-z
Subject(s) - polystyrene , dispersity , chemistry , polymer , analytical chemistry (journal) , mass spectrum , polymerization , mass spectrometry , radical polymerization , molar mass distribution , ion , polymer chemistry , chromatography , organic chemistry
A series of low‐polydispersity polystyrenes with molecular weight ranging from 2000 to 130000 synthesized by atom transfer radical polymerization were analyzed by time‐of‐flight secondary ion mass spectrometry. The polymer end groups obtained by this polymerization process are hydrogen at one end and bromide at the other end. The great sensitivity of these end groups towards the ion beam‐induced emission yield of secondary ion fragments allows the direct quantification of the molecular weight of the polystyrene at the surface. However, before applying any quantification method, several steps have to be performed: the peak assignment of the characteristic end group fragments and the choice of the spectrum normalization method. The influence of two normalization procedures is compared for two quantification methods—the characteristic peak intensity ratios and a chemometric method (principal component analysis)—in order to achieve molecular weight determination of the polystyrene at the surface. It is shown that, depending on the normalization procedure used, very different results can be obtained for both quantification methods. The validity of the procedures is also discussed. © 1998 John Wiley & Sons, Ltd.