Current Applications of 2D Nanonet-based Materials

Among the numerous analytical methods, the colorimetric strategy offers distinct advantages, being simple and economical and having the capacity for naked-eye detection, which make colorimetric sensors promising candidates for environment monitoring. Considerable efforts have been devoted to fabricating nanonet-based colorimetric sensors for various applications, including heavy metal detection, formaldehyde detection, L-ascorbic acid detection, and so on (Fig. 8.15B). A highly sensitive colorimetric sensor for the detection of formaldehyde based on a methyl yelloweimpregnated PA-6 nanofiber/net, which was prepared by Wang et al., presents an obvious color change from yellow to red under exposure to formaldehyde. And, the fascinating features of nanonets endowed the sensor with a naked-eye detection limit as low as 50 ppb. Li et al. reported the fabrication of a portable sensor strip using gold probes and nanonet membranes for naked-eye chromatic assaying of trace amounts of lead. Upon exposure to lead ions, the sensor strip exhibits a naked-eye-detectable color change of pink to purple with a low detection limit of 10 mg/dL. In addition, Wen et al. prepared a ready-to-use nanonet-based strip for L-ascorbic acid visual detection via a blend electronetting process . The incorporation of polyaniline into PA-66 nanonet membranes would allow the sensor strip to undergo a brown-to-green color transition upon 50 ppb L-ascorbic acid exposure.