Microencapsulation and characterization of poly(vinyl alcohol)-coated titanium dioxide particles for electrophoretic display

Titanium dioxide (TiO2) particles were coated by poly(vinyl alcohol) (PVA) via a simple method of coacervation without a conventionally practiced polymerization step. Transmission electron microscopy (TEM) images clearly showed that the successful coating was achieved on the surface of TiO2 particles. The average thickness of PVA coating layer was about 1.07 μm and the amount of coated PVA was 1.40 wt.% relative to TiO2. The existence of PVA layer on TiO2 was also verified from FT-IR spectra. The PVA-coated TiO2 particles were further microencapsulated via coacervation of gelatin and gum Arabic. Regarding the performance of the resulting microcapsules, the resulting PVA-coated TiO2 particles showed both a good electrophoretic movement and a good bistability in the microcapsules. Therefore, these microcapsules embedding PVA-coated TiO2 particles can be used as a good candidate for the electrophoretic displays.