Synthesis and characterization of low molecular weight oligomers of soluble polyaniline by electrospray ionization mass spectrometry

Mass spectrometry (MS) has not been utilized extensively for its ability to analyze the structure of polyaniline. This has been a result of polyaniline not being directly soluble in MS-"friendly" solvents. Here, low molecular weight oligomers of polyaniline are synthesized, using a modified room temperature synthesis of polyaniline, that are soluble in solvents that are better suited to electrospray MS analysis. Oligomers up to the 9-mer are identified from the mass spectra. Importantly, several different types of polyaniline oligomers that differ from one another based on their end groups were distinguished in the mass spectra. The use of tandem mass spectrometry (MS/MS) enabled identification of these various end groups.