Controlling the molecular weight of poly(2,5-bis[N-methyl-N-hexylamino]phenylene vinylene) using nitrobenzene as an inhibitor

Poly(2,5-bis[N-methyl-N-hexylamino] phenylene vinylene) (BAM-PPV) has been studied for several decades as an anti-corrosion coating. Although the polymer is readily synthesized via base-promoted radical chain polymerization, BAM-PPV exhibits poor solubility at high-molecular weights (M-w > 100 kDa), which limits its applications. In this work, the molecular weight of BAM-PPV was modulated with nitrobenzene. At nitrobenzene loading as low as 0.9 mol%, the polymerization reaction produced low-molecular weight BAM-PPV (M-w = 5-46 kDa). The polymerization of BAM-PPV was systematically studied via size-exclusion chromatography (SEC), liquid chromatography-mass spectrometry (LC-MS), and H-1 NMR spectroscopy, which revealed suppression of the dimer intermediate before chain polymerization. Collectively, this work could expand the practical applications of BAM-PPV for use in optoelectronic devices or corrosion inhibition coatings.

Automated summary

Poly(2,5-bis[N-methyl-N-hexylamino] phenylene vinylene) (BAM-PPV) has been studied for decades as an anti-corrosion coating, but its poor solubility at high molecular weights has limited its applications. This work shows that modulating the molecular weight of BAM-PPV with nitrobenzene can produce low-molecular weight polymers, expanding its practical applications in optoelectronic devices or corrosion inhibition coatings. Systematic studies of the polymerization process reveal the suppression of the dimer intermediate before chain polymerization.