Preparation and Characterization of Poly(urea formaldehyde) Microcapsules Containing Phthalocyanine Blue E-ink

Pigment phthalocyanine blue(PB) was purified and refined by recrystallization in alcohol solution to get 200-500 nm rodlike PB crystals. Octadecylamine was used to modify the surface and improve the dispersion in tetrachloroethylene of PB crystals. Microcapsules containing the PB Eink were successfully prepared by in situ polymerization of urea and formaldehyde. Scanning electron microscope (SEM) images showed that the microcapsules had a regular spherical shape with a particle size of 30-50 μm and a smooth surface. The optimum conditions of the preparation were confirmed as: the mass ratio of surfactant poly(vinyl alcohol) to urea, 0.2; reaction time, 3-4 h; pH, 3-4; stirring rate, 500-700 r/min.