Cyclization of Polyacrylonitrile Nanofibers Enhanced by Cu₂O During Electrospinning

This work uncovers a novel room-temperature cyclization pathway for polyacrylonitrile (PAN), facilitated by copper(I) oxide (Cu₂O) during electrospinning, paving the way for advanced material design of functional materials. Cyclization, traditionally requiring temperatures around 290 °C, is an essential step in carbon fiber production and the development of advanced functional materials. We demonstrate that thermal pretreatment and the incorporation of Cu₂O enable partial cyclization at ambient conditions, leading to the formation of nonaromatic structures such as azine and imine derivatives during electrospinning. The catalytic role of Cu₂O in influencing cyclization is confirmed by dedicated analytical studies showing a significant extent in its presence. Solid-state nuclear magnetic resonance spectroscopy (ssNMR) and Fourier-transform infrared spectroscopy (FTIR) reveal the chemical transformations induced by high-voltage during electrospinning, emphasizing the interplay between solution preparation, selection of catalysts, and electrospinning conditions. These findings highlight the significance of metal oxides in tailoring polymer chemistry within fiber structures and provide a foundation for exploring alternative catalysts to design nanofiber electrodes optimized for energy conversion applications.