Quantitative ToF SIMS Analysis of Spun-Cast and Solution-Cast Polymer Films

• Published in: International journal of polymer analysis & characterization Vol. 4; no. 2; pp. 133 - 151
• Main Authors: Leeson, Alistair M., Alexander, Morgan R., Short, Robert D., Hearn, Martin J., Briggs, David
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.12.1997
• Subjects: film thickness; molecular weight; poly(methyl methacrylate); Time-of-flight secondary-ion mass spectrometry (ToF SIMS)
• ISSN: 1023-666X; 1563-5341
• DOI: 10.1080/10236669708033942

Films of a series of monodisperse, moderately syndiotactic poly(methyl methacrylate) (PMMA) standards, with M w ranging from 2,900-428,000, were solution-cast and spun-cast from chloroform onto clean aluminium substrates. The polymers were thoroughly characterized by conventional spectroscopic and chromatographic techniques. The films were studied using x-ray photoelectron spectroscopy (XPS) and time-of-flight secondary-ion mass spectrometry (ToF SIMS). The effects of molecular weight and film thickness on SIMS spectra were investigated thoroughly by unit-mass and high-resolution ToF SIMS. Film thickness had a pronounced effect on the negative SIMS spectra, particularly in films a few monolayers thick. This was seen in both the total negative ion counts (m/z 31-200) and the key negative ion intensity ratios. A parallel effect was observed with respect to the effect of molecular weight. These differences are attributed to (i) the original end-group concentration in the surface which decreases with increasing molecular weight and (ii) the original end-group concentration in the surface which increases as film thickness decreases.