Pourbaix sensors in polyurethane molecular logic-based coatings for early detection of corrosion

Abstract

Corrosion is detected by logic-based molecules before it is visible to the naked eye.

Molecular engineering of fluorescent bichromophore 1,3,5-triaryl-Δ2-pyrazoline and 4-amino-1,8-naphthalimide molecular logic gates

“…For our logic studies we settled on using THF as the solvent taking into consideration the solubility of our oxidant Fe 3+ for oxidising 3 and to allow for comparison with published literature results. 40,46,59 The fluorescence spectra of 1–3 upon excitation of THF solutions at 440 nm are broad with maximum λ em at 520 nm, 510 nm and 530 nm (Fig. 6).…”

“…This latter logic gate type is of interest to us for application in the early detection of corrosion. 39,59 DFT calculations at the B3LYP/6-31+g(d,p) level provide additional insight into the frontier molecular orbitals (HOMO-LUMO levels) and photophysical characteristics.…”

Molecular Logic Gates Based on Ferrocene-Containing Compounds

“…The group of Magri has also reported on other MS-MLGs based on fused heterocycles with more extensive conjugated systems [40] (Figure 9). In these three molecules, the fluorophores are symmetric; thus, no regioisomers exist.…”

Lab-on-a-molecule and multi-analyte sensing

“…High levels of Na + , H + , and Fe 3+ are associated with various cancer cells, which tend to grow quicker than healthy cells, and therefore accumulate higher levels of various analytes. The same trio of analytes are also early warning markers for corrosion of steel and other ferrous metals ( Scerri et al, 2021 ), particularly for automobiles in colder geographic regions where NaCl is used for deicing snowy roadways.…”

“…In 1:1 (v/v) MeOH/H 2 O, the emission digitally switches “on” with a 25-fold enhancement and a Φ f of 0.203. The reader is reminded of the significance of this trio of analytes in corrosion detection ( Scerri et al, 2021 ). The related two-input AND logic gates simultaneously detect high levels of Fe 3+ and H + levels under conditions of excess Na + to accelerate the rate of corrosion of mild steel ( Scerri et al, 2021 ).…”