Halochromic Polymer Nanosensors for Simple Visual Detection of Local pH in Coatings

Smartphones spot first signs of metal corrosion

30 August 2021

A novel nanoparticle-based coating can reveal underlying corrosion in metals when scanned by a smartphone camera, potentially enabling early detection of metal structures that are at risk of failure due to corrosion damage.

The initial phases of metal corrosion can be difficult to detect by the naked eye. The process is accompanied by pH changes, but conventional pH detectors are designed to measure the acidity or alkalinity of liquids rather than solid surfaces.

Now, two researchers at the Vidyasirimedhi Institute of Science and Technology in Thailand have demonstrated a simple system that can measure pH on metal surfaces.

The pair developed a coating containing nanoparticles that feature two fluorescent dyes. The intensity of light each dye emits when exposed to ultraviolet light depends on the pH. Any local alteration in pH across the metal surface can be detected by a smartphone, allowing early corrosion detection.

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References

1. Nano Letters 21, 3604−3610 (2021). doi: 10.1021/acs.nanolett.1c00620