Preparation of pickering emulsion ink and its application in inkjet printing smart labels

In this paper, a new type of Pickering emulsion ink that can be used for inkjet printing is prepared. This ink uses alkalized maleic anhydride-styrene copolymer microspheres as the emulsifier, corn oil as the oil phase, and alizarin as a color indicator. The water-in-oil Pickering emulsion coated with alizarin is prepared by homogeneity, and the Pickering emulsion ink is prepared by added additive. The structure of the alkalized maleic anhydride-styrene copolymer microspheres was characterized by infrared spectroscopy, scanning electron microscopy, and particle size analysis; the structure and type of the Pickering emulsion were characterized by fluorescence microscopy; and the stability and viscosity of the Pickering emulsion were adjusted by the water-oil ratio and the emulsifier concentration; the surface adhesion and wettability of the Pickering emulsion ink on the substrate during the inkjet printing process were further studied. The smart label prepared by printing this ink exhibited high pH sensitivity and could be applied in the food freshness monitoring field.