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Abstract: In this paper, we demonstrate a simple approach to improve the electrochromic performances of polyaniline (PANI) by incorporating PANI nanofibers (PANI-NFs) synthesized by interfacial polymerization into water-soluble PANI:poly(styrene sulfonate) (PANI:PSS). The one-dimensional PANI-NFs endow spin-coated PANI film high electrochemical activities and electrochromic properties. The structures and morphologies of PANI-NFs were characterized by FTIR spectroscopy and SEM observation. The electrochemical behaviors of PANI/PANI-NFs composites were analyzed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochromic properties of composites were tested using electrochemical working station combining a UV-Vis spectrometer. The results show that the PANI-NFs with even diameter of ~ 30 nm can be synthesized easily using interfacial polymerization method. With the increasing of feeding amount of PANI-NFs, the oxidation peaks of CV curves shift to low potential direction, indicating enhanced electrochemical activities. The electrochromic test confirms that the PANI/PANI-NFs composites films have higher electrochromic contrast of 0.67 as comparison to 0.49 of PANI:PSS film. The PANI/PANI-NFs also exhibit excellent electrochromic stability. After 2000 cycles switching, only less than 4% contrast decay is observed. The enhanced electrochromic properties can be attributed to the small charge-transfer resistance and facile ion diffusion process brought by PANI-NFs. The EIS tests exhibit that with incorporating of highly conductive PANI-NFs, the PANI/PANI-NFs composites possess relatively lower charge-transfer resistance of 76 Ω as comparison to 94 Ω of neat PANI:PSS.Graphical abstract: [ABSTRACT FROM AUTHOR]

In this paper, we designed a novel organic-inorganic nanohybrid electrochromic material through tethering polyaniline and gold colloids with an interfacial coordinate bond. The enhanced electrochemical and electrochromic properties were expected owing to the high conductivities of the gold colloids and strong interfacial interaction between the organic phase and inorganic phase. The water-dispersible polyaniline-gold (PANI-Au) nanohybrids were synthesized successfully through grafting copolymerization of aniline with p -aminothiophenol (PATP) functionalized gold colloids in an aqueous system using a macromolecular acid, poly(styrene sulfonate) (PSS) as the dopant agent. The structures, morphologies, and electrochemical and electrochromic properties of PANI-Au nanohybrids were characterized by the UV–vis, FTIR, Raman spectrometers, SEM, and electrochemical working station, respectively. The results show that through incorporating gold nanoparticles into the PANI matrix with the interfacial coordinate bond, PANI-Au nanohybrids possess uniform nanoparticles morphologies with diameter ~180 nm. The electrochemical activity and the charge transfer process of PANI were enhanced, which is proved by the CV test and EIS analysis. As the results, the PANI-Au nanohybrids can switch at relatively lower potentials and give a higher optical contrast as comparison with neat PANI: PSS. With ~1.4 wt% Au loading amount, the contrast of PANI-Au nanohybrid is 0.97, which is much higher than 0.76 of PANI: PSS. The coloration and bleaching time are also shortened from 13.4 s and 8.9 s for PANI: PSS to 8.3 s and 7.6 s for PANI-Au-c, respectively. [ABSTRACT FROM AUTHOR]