Manipulation of silver nanocubes detection sensitivity to radical compounds by modifying their surfaces with...

We report a method for controlling the detection sensitivity to or the degree of etching of Ag nanocubes by radicals by modifying their surfaces with poly(acrylic acid) or poly(allylamine hydrochloride) for wide-range quantification of radical compounds. The degree of Ag nanocube etching is influenced by the concentrations of the polyelectrolytes used for modification. These polyelectrolytes protect the Ag nanocubes, probably by either retarding (forming diffusion barriers) or preventing (blocking/entrapping/scavenging) the arrival of radicals to Ag nanocubes, or both. The weights of the two roles are different depending on the polyelectrolyte type; therefore, the sensitivities of Ag nanocubes are also influenced by this factor. The roles of the polyelectrolytes were demonstrated by using radical compounds produced from tetrahydrofuran and H2O2 and further confirmed with Ag nanospheres. Using the results, the radical sensitivities and detection ranges of polyelectrolyte-modified Ag nanoparticles could be manipulated. Moreover, we produced calibration curves for the wide-range quantification of radical compounds.