Applied Surface Science, Vol.252, No.19, 7224-7227, 2006
SIMS depth profiling of deuterium labeled polymers in polymer multilayers
Thin planar polymer films are model systems for probing physical phenomena related to molecular confinement at polymer surfaces and polymer/polymer interfaces. Existing experimental techniques such as forward recoil spectrometry (FRES) and neutron reflectometry (NR) have been used extensively for analysis of these systems, although they suffer from relatively low depth resolution (FRES) or difficulties associated with inversion to real space (NR). In contrast, secondary ion mass spectrometry (SIMS) can provide real-space depth profiles of tracer labeled polymers directly with sufficient depth resolution for optimal analyses of these systems. Deuterated polystyrene (dPS) has been employed as the tracer polymer and has been embedded in a matrix of either unlabeled polystyrene (PS) or poly(cyclohexyl methacrylate) (PCHMA). These doped films have been placed on either poly(methyl methacrylate) (PMMA) or poly(2-vinyl pyridine) (P2VP) and thermally annealed. Varied analysis conditions for a magnetic sector SIMS instrument (CAMECA IMS-6f) were used to optimize the depth resolution and detection sensitivity while minimizing matrix effects and sample charging. Both Cs+ and O-2(+) primary ions have been used along with detection of negative and positive secondary ions, respectively. Impact energy and primary ion species have been shown to affect matrix secondary ion count rate for the various films studied. (c) 2006 Elsevier B.V. All rights reserved.