Patent ID: 8298298

Claim:
A method of dying a substrate, the method comprising: contacting the substrate with an aqueous solution of a dye compound for a time period sufficient to covalently bond a hydrophilic dye moiety of the dye compound to the substrate; and exposing the substrate to a stimulus; wherein: the dye compound comprises: the hydrophilic dye moiety; and a hydrophobic moiety bonded to the hydrophilic dye moiety through a linker moiety; and the linker moiety is configured to be cleaved in response to a stimulus; the dye compound is represented by Formula I, II, III, or IV: Z is the hydrophobic moiety; L is the linker moiety; Y is a phenyl or a naphthyl group; X is H, Cl, Br, F, or I; R a is a halogen, or —NR b —W group; R b is H or an alkyl group; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , and R 7 may be the same or different and are independently H, Cl, Br, F, I, —NO 2 , —OH, alkyl, aryl, or —S(═O) 3 R 12 ; R 8 , R 9 , R 10 , and R 11 may be the same or different and are independently H or alkyl; R 12 is H or an alkali metal; each Y independently comprises a phenyl or a naphthyl group; and W comprises a phenyl, naphthyl or anthracenyl group.