Encapsulation of TiO2 in poly(4-vinyl pyridine)-based cationic microparticles for electrophoretic inks

Poly(4-vinyl pyridine) microparticles were prepared via surfactant-free emulsion polymerization in water with divinylbenzene as crosslinking agent. The synthesis was adapted for the encapsulation of TiO2. The size, integrity and nature of the resulting hybrid microparticles were investigated by Scanning electron microscopy, Dynamic light scattering and Fourrier-transform infrared Spectroscopy measurements. The particles were quaternized using a modified copolymer, which was grafted via an alkylation reaction on particle surface followed in a second step by alkylation with methyl iodide. After quaternization, an electrophoretic ink was formulated using the TiO2/poly(4-vinyl pyridine) cationic microparticles. Under electric field, the electrophoretic ink showed good optical properties, lifetime and stability.