Alumina nanocoating assisted dispersion stability of permanent violet pigments via atomic layer deposition

Permanent violet is an organic pigment that is extensively applied in the colourant industry, wherein excellent dispersion ability and stability of organic pigments in a solution is required. Therefore, surface modification of organic pigments significantly impacts their application performance. Herein, a few-nanometres-thick inorganic film coating layer via atomic layer deposition (ALD) method has been prepared for surface modification of permanent violet pigments, which enhances the pigments’ dispersion stability. Uniform coatings comprising individual particles (rather than agglomerates) are confirmed by morphology, specific surface area and particle size distribution characterizations. The UV–Vis absorbance results indicate 20 cycles of Al 2 O 3 coated permanent violet pigments exhibit excellent stability when dispersed in ethanol solvent, which is attributed to the electrostatic stabilization of Al 2 O 3 coatings. The ultrathin film coating provides an effective method of improving the dispersion stability of organic pigments, which can promote the applications in electronic colouration industry.