Understanding the role of epoxy emulsifiers in water-borne epoxy coatings with the aggregation-induced emission approach

Emulsifiers in water-borne epoxy coatings play an essential role in the performance of the coatings. They typically keep coating formulations well-dispersed. However, depending on the emulsifier type, quantity, and properties, the final coating will perform differently. The underlying role and mechanism for any emulsifier in a coating formulation is key to predicting the final properties of coatings. However, to study these two is challenging and not straightforward as coatings have several other contents. In this work, we employed the theory of aggregation-induced emission (AIE) to study the role of epoxy emulsifiers in water-borne coatings. AIE offers the advantages of change in the emission of the AIE luminogens (AIEgens) depending on their nanoscale environment to understand the interaction of materials with a fast, contactless, nondestructive, and visual means. In this work, AIEgens were grafted to epoxy emulsifier into the coating formulations to endow the coating with the fluorescent property, then used to study the coating interaction environment. The interaction between the components and the properties of fluorescent coating dispersions were studied in real-time by reading the fluorescent properties of the final coatings. •The interaction between the epoxy emulsifier and epoxy resin in the preparation and curing processes for waterborne epoxy coating was traced in real-time with the help of restriction/unrestriction of AIEgen molecular rotors.•An easy way to explore the corrosion mechanism of the waterborne epoxy coating is found by studying its fluorescence behavior according to the RIR mechanism.