Formation of square prism-shaped poly(o-phenylenediamine) fibers triggered by high ionic strength

Abstract

A simple bottom-up method to fabricate novel square prism-shaped poly(o-phenylenediamine) (PoPD) hierarchical fibers is presented. PoPD oligomers obtained by H₂O₂ oxidizing o-phenylenediamine (oPD) monomers were triggered to aggregate into fibers by high salt solution. The fibers were fully characterized by SEM, FTIR, XRD, UV-vis spectra, and thermogravimetric techniques. Their stability when treated with high temperature in water, acidic solution and ethanol solution was investigated, which showed three different disassembly patterns due to disruption of non-covalent interactions inside the fibers. It was very interesting that PoPD fibers exhibited a strong fluorescence property (emission at 527 nm) after alkali treatment.