Preparation and characterization of carbon black/acrylic copolymer hybrid particles for dual particle electrophoretic display

To prepare black electrophoretic particles with good suspension stability in the low dielectric medium for electrophoretic display application, four kinds of carbon black (CB)/acrylic copolymer hybrid particles, CB/poly(2-hydroxyethyl acrylate-co-lauryl methacrylate) (P(HEA–LMA)), CB/poly(2-hydroxyethyl acrylate-co-2-ethylhexyl acrylate) (P(HEA–EHA)), CB/poly(2-(dimethylamino)ethyl methacrylate-co-2-ethylhexyl acrylate) (P(DMA–EHA)) and CB/poly(2-(dimethylamino)ethyl methacrylate-co-lauryl methacrylate) (P(DMA–LMA)), were prepared via polar bonding, the interaction between the carboxyl groups on the surface of CB and the hydroxyl or amino group in copolymers. Structure, morphology as well as electrophoretic properties of the particles were examined. The particle size of the P(HEA–EHA) and P(DMA–EHA) treated CB increases with increasing the storage time. While the particle size of the P(HEA–LMA) and P(DMA–LMA) treated CB is time independent, which can be attributed to the better extension of P(LMA) segments in tetrachloroethylene than P(EHA) and the resulting more effective steric effect. When the feed ratio of DMA/LMA was 3:5 by volume, the maximum values of the electrophoretic mobility and Zeta potential reach 5.44 × 10−10 m2 V−1 s−1 and 32.5 mV, respectively. The P(DMA–LMA) anchored CB particles can be applied in the dual-particle electrophoretic dispersion together with negative charged TiO2 to show black and white images.