| Abstract
| - Electrochromic and charge capacity are easily manipulated in layer-by-layer films from polyaniline and V2O5. This self-assembly method allows the control of the chromogenic properties of polyaniline in an inorganic matrix with high capability of lithium insertion.
- This work describes how manipulation at the molecular level of V2O5/polyaniline (PANI)nanocomposites built with the layer-by-layer (LBL) technique promotes enhancement ofcharge storage capability, new electrochromic effects, and control of ionic flux. By changingthe film architecture we control the amount of PANI participating in the redox processes ofthe LBL films. As a consequence, the films display the electrochemical profile of V2O5 andthe chromogenic properties of PANI. Impedance spectroscopy data show the presence ofdistinct phases in the nanocomposite, which allows a conducting path for the whole potentialrange between 0.5 and −1.5 V. Further control of the properties of the nanoarchitectures isachieved by adsorbing V2O5/PANI LBL films onto a cast PANI film. By changing the timeof immersion of the PANI−V2O5/PANI system into a solution of LiClO4/propylene carbonate(PC), we were able to monitor the mass gain/loss (Δm) with an electrochemical quartz crystalmicrobalance (EQCM) as a function of charge (q) and control the intercalating/deintercalatingspecies. The Δm/q ratio shifted from 0.77 to −0.12 mg C-1 when a 10-bilayer LBL film wasimmersed into a solution of LiClO4/PC during 24 h, indicating a change from an anioniccontribution to a cationic one for the charge compensation process. It is envisaged that themolecular-level control demonstrated here may be exploited in producing efficient lithiumbatteries as well as electrochromic devices and sensors.
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