Fast-response and monodisperse silica nanoparticles modified with ionic liquid towards electrophoretic displays

The facile synthesis of electrophoretic particles for electrophoretic displays (EPDs) with fast response and precise image control is a challenge. In this work, monodisperse silica nanoparticles were prepared by a sol-gel process in reverse microemulsion combined with solvent-thermal treatment, and modified with ionic liquid. The silica nanoparticles before and after surface modification are all monodisperse and smooth spheres. They also own suitable densities and excellent chromaticity for EPDs. The structure of ionic liquid modifiers shows remarkably influence on surface property and electrophoretic property of modified silica nanoparticles. The modified silica nanoparticles show improved hydrophobicity favoring for dispersion stability and suspension stability in the dispersant. The surface charge performance of modified silica nanoparticles are depending on competitive cooperation between ion pairs and alkyl groups of ionic liquids, and can be adjusted through tuning ionic liquid structure. The fabricated EPD prototypes show response time of 180–191 ms in the electrophoretic display cell with 0.2 mm thickness, much faster than the commercial EPDs.