Polyelectrolyte-Functionalized Corona–Shell Integration of Iron Oxide Nanoparticle for Electrophoretic Control

Paper-like feel, high contrast, and ultralow power consumption feature prominently in electrophoretic displays and are widely used in electronic readers, tags, blackboards, and other fields. But most of the commercially mature electrophoretic systems remain in black-white pattern and badly need color electrophoresis to meet higher display demands. So, we first modified the integration surface of iron oxide nanoparticle with silica shell and polyethylenimine corona together using an improved one-pot Stöber method, resulting in red electrophoretic particles with a mean size of about 300 nm and a high potential of over +100 mV. By incorporating white nanoparticles, we successfully achieved alternating red-white electrophoretic display with a contrast ratio of 1.54, demonstrating a short response time of 550–1100 ms and a recovery time of 770–1210 ms. It is anticipated to provide a facile reinforcing approach to electrophoretic ink for color electrophoresis.