Figure 10.
Modulation of Droplets by Cu Ions and Fluorometric Visualization
(A) Droplets passing through polyaniline-coated fabrics doped with CuSO4 can dissolve Cu ions. A Nc/PMMA film spin-coated on a coverglass was used as a fluorometric detector to capture the droplets, which was then imaged by FQM. The Cu-modified droplets can quench the fluorescence of their underlying Nc dye and thus appear as dark spots under FQM.
(B) Fluorescence image of a control sample of Cu-free droplets on the detector film, showing drying marks of droplets, which did not quench the fluorescence.
(C) Fluorescence image of another control sample of Cu-containing droplets on the detector film. The stains quenched fluorescence strongly and appeared as dark spots.
(D) Transmission mode of image of a sample collected after they passed a Cu-loaded gauze, which clearly shows the drying marks of the droplets, but cannot differentiate which droplets were modified with Cu.
(E) Under fluorescence mode, Cu-modified droplets are clearly visible as dark spots. The yellow circles highlight modified droplets and the red circles mark the unmodified ones. A total of 18 out of 58 droplets were modified. All scale bars represent 50 μm.