First fabrication of electrowetting display by using pigment-in-oil driving pixels

We report the first fabrication of pigment particle-based electrowetting display (EWD) by using the requisite poly(isobutylene)-imide (PIB-imide) for effectively dispersing insoluble colorant in decane/water system. The series of PIB-imide dispersants were prepared from the amidation/imidation of PIB-succinic anhydride with different hydrophobic lengths and a suitable amine. The structurally tailored dispersants by adopting the highly hydrophobic PIB tails allows the formation of homogeneous dispersion of nanosized pigment particles in decane and clearly separated from water. The pigment dispersion at particle size of ca. 100 nm and a low viscosity of 2-3 cps was obtained and fabricated into an EWD device which was operated at a driving voltage of 15-20 V in achieving a maximum aperture ratio of 80%. With the advantage of both fast response time and vivid color, the pigment-based EWD, as shown in the video, stands out as a promising new option for future transparent display and serves as a critical foundation for the next-generation advanced display applications.