Microfluidic Confinement for Constructing Chiral Helical Polyacetylene-Based Monodispersed Circularly Polarized...

Circularly polarized luminescent (CPL) microspheres have attracted increasing attention due to their unique chiroptical properties and broad application prospects. However, the controlled fabrication of CPL microspheres with uniform size and regular morphology remains a significant challenge. Herein, we report a microfluidic confinement strategy that enables the precise preparation of CPL-active microspheres based on chiral helical polyacetylene. A theoretical model describing the two-stage droplet formation mechanism (filling and extrusion stages) is established, quantitatively correlating microdroplet size with key parameters such as flow rate, solution concentration, viscosity, and interfacial tension. Microfluidic simulations and systematic experiments validate the model, demonstrating that the microdroplet diameter can be precisely tuned by adjusting the polyacetylene concentration and the continuous phase flow rate. Under optimized conditions, chiral fluorescent microspheres with narrow size distribution and tunable diameters ranging from 4.85 to 13.37 μm are successfully fabricated. Furthermore, by employing a water-in-oil-in-water microfluidic chip, core-shell microspheres with mononuclear-monoshell and multinuclear-monoshell architectures are achieved. The obtained microspheres exhibit uniform fluorescence distribution, stable chiroptical activity, and intense CPL performance with luminescence dissymmetry factor of up to 0.025. This work provides a robust and versatile platform for the controlled fabrication of CPL microspheres with tunable size and morphology.