Microencapsulated electric ink using gelatin/gum arabic

Gelatin/gum arabic (GA) microcapsules were prepared by a convenient one step complex coacervation, in which TiO₂ nanoparticles modified by stearic acid (SA) and homodispersed in tetrachloroethylene (TCE) were encapsulated. The modified TiO₂ was characterized by Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS) and optical microscopy, etc. And the effects of various microencapsulation parameters were also experimentally investigated. It was shown that SA-coated TiO₂ nanoparticles are capable of subsidence-resistance in TCE as the SA is bonded to the surface of TiO₂ nanoparticles through esterification. In addition, under the optimal encapsulated condition, the microcapsules can be prepared with regular morphology and transparent and smooth surface. Finally, the particles in microcapsules possessed reversible response to dc electric field and the response time is ∼280 ms.