New electroactive and photosensitive polyamide/ternary LDH nanocomposite containing triphenylamine moieties in its backbone: synthesis and characterization

Abstract

The new ternary (Mg–Zn–Al–) layered double hydroxide (LDH) with an organic modifier-containing azo group (LDH–SHDBS) as a guest anion was prepared by a co-precipitation through one-step synthetic method. The novel electroactive polyamide (EPA) was successfully prepared by direct polycondensation reaction of azelaic acid with a new synthetic diamine 4. The structure of diamine 4 was confirmed by FTIR and 1H NMR spectra. Also, polyamide/ternary LDH nanocomposites were prepared by resulting EPA and modified ternary LDH under ambient condition. The resulting data using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) showed ternary LDH were successfully distributed into the EPA matrix. Thermal behavior of the EPA and its nanocomposites were studied by thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG). The presence of LDH layers into EPA matrix improved thermal stability (T5, T10, char yield) in both air and nitrogen atmospheres. Also, photoisomerization and electrochemical behaviors of EPA and resulting nanocomposites were measured using UV–Vis spectroscopy and cyclic voltammetry (CV), respectively. The UV–Vis spectrum of the obtained nanocomposites showed two peaks at λmax = 422 and 480 nm related to π–π∗ and n–π∗ transitions of trans azobenzene. Moreover, trans to cis isomerization of azomoieties was studied by irradiation of the nanocomposites under 254 nm photons. The CV pattern of EPA exhibited a reversible anodic peak around 0.84 V, corresponding to the nitrogen atom of triphenylamine unit into polymer backbone that improved by incorporation of LDH–SHDBS into EPA matrix.