Enhancing the electrochromic properties of polyaniline via coordinate bond tethering the polyaniline with gold colloids

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.