LAUSR

Abstract Two copper phthalocyanine blue pigments, C.I. Pigment Blue 15 (B) and C.I. Pigment Blue 15:3 (BGS), were modified with Single layer graphene(G) or graphene oxide(GO). The modified pigments were then characterized using FTIR spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption/desorption isotherms and thermogravimetric analysis. The modifications did not affect the chemical structure of the original pigments but non-covalent interactions between the phthalocyanine pigments and the G (or GO) did form. This greatly reduced aggregation and resulted in more uniform particle size distributions. Modification with both G and GO also resulted in a sharp decreases in the phthalocyanine emission intensities and there were small red-shifts in the absorption peaks. The modification of the pigments also improved their color strengths (116.6–121.4% for B and 106.0–108.8% for BGS), and modification with G improved the color purity. Finally, modification with GO improved the wettability of the original pigments. This is due to the abundant hydroxyl and carboxylic acid groups in graphene oxide.