Quantification issues in ToF-SSIMS and AFM co-analysis in two-phase systems, exampled by a polymer blend

This study concerns the measurement of the surface properties of sensitive materials, exampled by a polymer blend of polyvinyl chloride (PVC) and polycarbonate (PC), by static secondary ion mass spectrometry (SSIMS) and atomic force microscopy (AFM) operated in force modulation microscopy mode. it is shown that SSIMS, although damaging the surface little, causes significant subsurface damage. This changes the material behaviour in the irradiated region and leads to changes in the AFM measurements of both the topography and nanomechanical parameters such as the elastic moduli. Alternatively, if AFM is conducted first, contact with the tip may lead to modification of the surface. In order to minimize damage, soft cantilevers (spring constant similar to0.1 N m(-1)) are used. It is recommended that analyses be conducted on identifiably equivalent or partially overlapping regions, where any damage effects may be separated. Because, in SSIMS, a flood gun neutralizer must be used that irradiates the whole sample, it is recommended that AFM analysis is conducted prior to SSIMS even if different areas of the same sample are to be studied. The fractional areas identified by atomic species in SSIMS and separately by AFM are both the same and give the consistent ratio PVC/PC = 44:56. Both of these analyses are characteristic of the substrate below the top monolayer. The fractional areas determined using molecular species in SSIMS and by G-SIMS both give PVC/PC = 20:80, which is interpreted to show that more than half of the PVC surface is covered by a monolayer of PC. Crown Copyright (C) 2003.