New corrosion sensor for reinforced concrete requires no external power source. Steel corrosion causes enormous economic damage every year, which could be reduced by installing suitable monitoring devices. These should be simple, reliable and durable and should not require any maintenance or servicing. The present electrochromic device is designed to use the macrocell current of an active, chloride-induced corrosion element as an energy source to trigger a colour change. In this way, the system remains inactive until corrosion occurs. The device consists of diheptyl viologen in a liquid polymer electrolyte of LiClO4 and poly(ethylene glycol). The addition of viologen lowers the resistance but does not cause any further changes in the electrochemical properties of the polymer electrolyte. The impedance spectra indicate that ion transport rather than capacitive effects dominate the electrochemical properties. Experiments with direct current in the μA range show electrochromic switching times of several minutes, which is sufficient for the intended monitoring application.
T. Juraschek, O. Weichold
Development of an electrochromic device triggered by the macrocell current in chloride‐induced corrosion of steel‐reinforced concrete
J. Phys. Org. Chem. 2017, e3739. https://doi.org/10.1002/poc.3739
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