Pigment based inks are provided. The inks include a non-polar carrier fluid and a surface-functionalized pigment particle including a nitrogen-linked moiety to the surface of the pigment particle through a nitrogen link at one end of the nitrogen-linked moiety and a graft copolymer having two or three blocks attached at another end, the pigment particle suspended in the non-polar carrier fluid, the nitrogen-linked moiety further including an alkyl chain interposed between the nitrogen-linked moiety and the graft copolymer having the structure (I), where X is the nitrogen-linked moiety and Y is a copolymer, and the letter a is an integer between 0 and about 5,000, while the letter b is an integer of 2 or more.