Stereoregular polypropylenes studied by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and atomic force microscopy (AFM)

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and atomic force microscopy (AFM) were utilized to characterize polypropylenes of different stereoregularity (atactic, syndiotactic and isotactic) deposited on gold- or silver-coated mica surfaces. The AFM images clearly revealed distinctive surface topographies among the three types of polymers, which are largely due to their stereoregularity and crystallinity, The ToF-SIMS data showed distinguishable differences among the fragmentation spectra obtained from these polypropylene samples, especially in the low-mass region, Variations in the cluster structures were also detected. Supporting metal substrates had significant influence on fragment ion formation. Our results suggest that mass spectrometry and AFM could be used together to obtain supplemental information to NMR measurements of polymer stereoregularity. Copyright (C) 1999 John Wiley & Sons, Ltd.