A focus on the features of polyaniline nanofibres prepared via developing the single crystals of their block copolymers with poly(ethylene glycol)

Abstract

Poly(ethylene glycol) (PEG)-polyaniline (PANI) diblock and triblock copolymers were synthesized via copolymerization of aniline with amine-terminated PEG by interfacial polymerization using sulphuric acid as dopant and ammonium peroxydisulfate (APS) as well as potassium hydrogen diiodate (PHD) as oxidants. The PHD-based synthesized PANI nanorods possessed longer lengths, narrower diameter distribution and higher conductivity. The electroactivity of synthesized copolymers was characterized using ultraviolet-visible (UV-Vis) spectrometry, cyclic voltammetry (CV) and resistivity measurement. Even in the presence of dielectric PEG blocks, the synthesized block copolymers had a conductivity around 3 S cm-1. In a further step, the solution-grown single crystals were prepared to investigate the general features of grafted PANI nanorods using small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Based on AFM and SAXS analyses, the bimodal gel permeation chromatography (GPC) traces obtained from the block copolymers were originated from the diameter distribution of nanofibres, not from the dispersity of their lengths and molecular weights.