In situ visualization and real-time tracking of emulsion and miniemulsion polymerization at the microscale via fluorescence imaging

We report a simply designed liquid sample cell to visualize the processes of emulsion and miniemulsion polymerization by real-time fluorescence imaging of aggregation-induced emission fluorogens (AlEgens) in the emulsions. A unique phase separation phenomenon was observed in the styrene droplets during miniemulsion polymerization, which is beneficial for surface engineering of the polymer nanoparticles. Accordingly, a process intensified synthesis approach to polystyrene (PS) nanodispersion via emulsifier-free miniemulsion polymerization was developed in rotating packed bed reactors. Superhydrophobic fluorescent PS nanoparticles are fabricated via a cost-effective approach and exhibited a water/air contact angle of over 155 degrees, which are promising for fluorescent liquid marbles. These findings not only provide the basis for real-time tracking and characterization of polymerization processes at the microscale via fluorescence imaging of AlEgens, but also offer a new route for the cost-effective production of superhydrophobic polymer nanoparticles for advanced applications. (C) 2019 Elsevier Ltd. All rights reserved.