Electrochromic properties of some bis-chalcone derivatives-based nanofibers

Two bis-chalcone derivatives, (2E,6E)-2,6-bis[(thiophen-2-yl)methylene]cyclohexanone (C1) and (2E,6E)-2,6-bis[(furan-2-yl)methylene]cyclohexanone (C2)-based electrochromic (EC) nanofibers were produced in the presence of poly(methyl methacrylate) (PMMA) as supporting polymer using the electrospinning technique. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy were used to examine morphology and chemical compositions of nanofibers before and after stability test. SEM images of the obtained smooth and bead-free nanofibers before the stability test showed that both bis-chalcone derivatives were homogeneously dispersed on the surface of the electrospun nanofibers. Nanofibers of bis-chalcone derivatives were characterized with Fourier-transform infrared spectroscopy. The electrochemical and EC properties of these bis-chalcone derivatives were investigated. The C1-PMMA nanofiber-based electrochromic device (ECD) showed higher T-max (41.47%) than that of the C2-PMMA nanofiber-based ECD (4.67%) during coloration/bleaching at 715 nm. The switching times for coloration and bleaching of C1-PMMA nanofiber-based ECD were found to be 4.42 and 1.12 s, respectively, and the coloration efficiency was 136.18 cm(2)/C. Repeated cyclic voltammograms and 1000 cycles of chronoamperometric measurements of the bis-chalcone derivatives indicated that ECDs have long-term redox stability. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46010.