An effective and scale-up self-assembly route to prepare the rigid and smooth oligo(o-phenylenediamine) microfibers in acidic solution by NaClO2

Oligo(o-phenylenediamine) (OoPD) microfibers were successfully synthesized in acidic solution by mixing o-phenylenediamine (oPD) and NaClO2 solutions together. As proved by the mass spectroscopy (MS), 1H nuclear magnetic resonance spectroscopy (1H NMR) and Fourier transform infrared spectroscopy (FTIR), the OoPD is composed of 2,3-diaminophenazine and 2,2’-diaminoazobenzene. Based on the scanning electron microscopy (SEM), these microfibers were observed to be rigid and smooth. However, the smooth microfibers became the saw-like materials when pH value of oPD solution increased. The method used is facile and large-scale.