Multifunctional hyperbranched polyamide: Synthesis and properties

A novel multifunctional hyperbranched polyamide bearing oligoaniline, azobenzene and triphenylbenzene (PAOAF) has been prepared through a pyridine/LiCl-mediated acylation reaction. The structure of PAOAF was confirmed via nuclear magnetic resonance (NMR), Fourier-transform infrared spectra (FTIR), X-ray diffraction (XRD) and gel permeation chromatography (GPC). The thermal stability was probed via thermogravimetric analysis (TGA). The electrochemical activity of PAOAF was explored by cyclic voltammetry in 1.0 M H2SO4 confirming a surface controlled process. Tunable dielectric property of PAOAF has been accomplished by controlling the isomerization of azobenzene groups using UV/Vis irradiation. The electrochromic performance of a PAOAF/ITO electrode was studied by spectrochronoamperometry in detail, exhibiting good electrochromic properties with high contrast value and satisfactory coloration efficiency. Moreover, the fluorescence of PAOAF was modulated by controlling the oxidation degree of oligoaniline segments because of the energy migration occurring between oligoaniline and triphenylbenzene groups.