Size-Controlled Microbeads via Oil-in-Oil Pickering Emulsion for High-Percolation Network in Polymer Composites

With increasing demand on polymer composites containing high-performance and expensive materials, polymer composites with high-percolation network at low filler content have been crucial. Polymer composite fabricated from filler-coated polymer core-shell microbeads via hot pressing is promising for achieving high-percolation network at low filler content, readily confining fillers to interface between polymer microbeads. Among the various method for synthesizing polymer microbeads, emulsion polymerization is widely used due to its advantage of scalability. Although Pickering emulsion polymerization is promising part of emulsion polymerization and facilitate to adsorb solid Pickering agent on interface, subsequently forming a core-shell structure, conventional aqueous Pickering emulsion polymerization restrict available material to water-insensitive monomers. Here, to overcome this challenge, we fabricate polymer microbeads using oil-in-oil Pickering emulsion polymerization. Two types of organic solvent were introduced for dispersed and continuous phases, respectively. 2D materials modified with alkylamine was used as Pickering agent and exhibit robust stability because of large specific surface area. Also, we successfully tailored size of polymer microbeads by modulating the method of applying shear force during emulsification process. This size control can tune the filler density and interfacial area in the final composite. In summary, this work provides a versatile strategy for high-percolation network in polymer composite via hot-pressing process with water-sensitive polymer microbeads, implying significant potential for composite application.