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A study of the interfacial chemistry between polymeric methylene diphenyl di‐isocyanate and a Fe–Cr alloy
Author(s) -
BañulsCiscar Jorge,
Trindade Gustavo F.,
Abel MarieLaure,
Phanopoulos Christopher,
Pans Griet,
Pratelli Daniele,
Marcoen Kristof,
Hauffman Tom,
Watts John F.
Publication year - 2021
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/sia.6922
Subject(s) - x ray photoelectron spectroscopy , sputtering , secondary ion mass spectrometry , chemistry , methylene , ion , analytical chemistry (journal) , cluster (spacecraft) , static secondary ion mass spectrometry , argon , thin film , materials science , chemical engineering , nanotechnology , organic chemistry , computer science , engineering , programming language
The interactions of polymeric methylene diphenyl di‐isocyanate (pMDI) and a model Fe–Cr alloy have been studied by X‐ray photoelectron spectroscopy (XPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). Films of two different thicknesses have been investigated: one with an extremely thin pMDI layer in which the interfacial chemistry can be probed directly and a thicker one in which sputter profiling using cluster ions is necessary to expose the interface chemistry for direct analysis. Multivariate analysis (MVA), using principal component analysis (PCA) and nonnegative matrix factorisation (NMF), has been used to identify specific ions associated with the interfacial region of the ToF‐SIMS sputter depth profile and chemical species from the XPS sputter depth profile. As an unsupervised method, this avoids an unconscious bias on the part of the analyst. Specific ions associated with pMDI interactions with both Fe and Cr allow the proposal of two complementary reaction mechanisms, supported by the XPS data. A range of cluster ions is used in this investigation, but the bulk of the work used argon clusters for the XPS depth profiles and Buckminster Fullerene projectiles for the ToF‐SIMS analyses. To ensure that such data were directly comparable, the ToF‐SIMS sputter profiles were repeated in a different system of the same type using argon cluster ions.