Visual Detection of Thiocyanate Based on Fabry-Perot Etalons with a Responsive Polymer Brush as the Transducer.

The detection of thiocyanate (SCN-) is particularly important in industrial effluents and biological fluids because of the toxic nature of SCN-. Herein, a metal-insulator-metal (MIM) resonator for visual detection of SCN- is presented based on a poly[(2-(methacryloyloxy)ethyl) trimethylammonium chloride] (PMETAC) brush. The MIM resonator exhibits obvious color change as the concentration of SCN- changes, which can be easily distinguished by the naked eyes. In addition, the as-prepared MIM resonator also shows the advantages of good anti-interference, excellent reusability, and fast response rate. Combining the above advantages, the proposed MIM resonator may provide a broad perspective for a wide variety of visible-light applications.