TGA-GC-MS quantitative analysis of phosphorus-end capped functional polymers in bulk and ultrathin films

An hyphenated method based on thermal gravimetric, gas chromatographic and mass spectrometric analyses (TGA-GC-MS) is proposed for the quantitative analysis of diethylphosphate-end capped polymers with varying chain length, in bulk and as ultra thin film. The method fully calibrated and validated, revealed a powerful and affordable tool in the determination of the amount of phosphorous in polymeric samples but also it allows the determination of the number of repeating units per chain end. Compared to the common techniques, namely NMR spectroscopy and ICP-MS, no sample pretreatments are required. Consequently, polymeric films supported on inert substrates can be directly analyzed. The quantitative calibration, obtained for bulk materials, was demonstrated to be accurate also for films of different thickness. In this frame, the method revealed highly sensitive thus allowing the phosphorous determination even in ultrathin films with thickness of few tens of nanometers. Finally, the chromatographic profile of the species evolving during the thermal degradation was found to depend on the polymeric film thickness. This implies that information concerning the polymer stability and degradation mechanism at different size scale can be obtained. Considering the widespread interest for thin and ultrathin films of polymers containing phosphorous groups for brush-based technologies, the proposed method can be helpful in various areas, including flame retardant material, healthcare and medicine, microelectronic, for facile and precise characterization of functional interfaces.