Spray‐n‐Sense: Sprayable Nanofibers for On‐Site Chemical Sensing

Abstract

Abstract A versatile “Spray‐n‐Sense” sprayable nanofiber technology for on‐site chemical detection is demonstrated. Driven by compressed gas, the “Spray‐n‐Sense” nanofibers, as the name suggests, can be directly sprayed onto any kind or shape of surfaces, while the embedded chemical reporter enables simple colorimetric/fluorometric detection. Herein, nanofibers are sprayed on several surfaces including cardboard, glass, plastic, and rubber. The sensing capabilities of the “Spray‐n‐Sense” nanofibers are established through the detection of three different analytes including two metal ions (Fe 2+ and Fe 3+ using 1,10‐phenanthroline and curcumin as chromogenic reporters, respectively) and ammonia (using rhodamine‐B as a fluorogenic reporter) in aqueous media. Additional to being highly portable, the “Spray‐n‐Sense” nanofibers show impressive sensor characteristics with a sub‐ppm lower limit of detection (LLOD) for Fe 2+ and a wide linear working range. Whereas, the LLOD of 6.2 and 32 ppm is achieved for Fe 3+ ions and ammonia, respectively. A custom‐designed smartphone application enables quantitative analysis for reliable on‐site sensing. The selectivity and specificity are imparted by the embedded reporter, and thus allow analyte detection in complex real‐life samples and simultaneous detection of multiple chemical species through co‐doping. The “Spray‐n‐Sense” nanofibers also allow for the detection of target analytes in solid samples.