Carbon black and titanium dioxide have been widely used as pigment particles for electrophoretic displays. However, the effect of external water vapor on these pigment particles has not yet been presented. Therefore, in this work, we report the clumping phenomenon between pigment particles as a result of water vapor absorption. To verify clumping between pigment particles, various analysis techniques were used, including scanning electron microscopy, atomic force microscopy, zeta potential measurement, and Raman spectroscopy. We examined the Raman spectrum of carbon black to demonstrate the effect of water vapor absorption on particles. According to the Raman spectrum analysis, the 2D and 2D' peak intensities were significantly increased; moreover, the full widths at half maximum were modified. Thus, we concluded that water vapor absorption on pigment particles can induce the clumping phenomenon on pigments. To protect an electrophoretic display device from external gas transmission, we applied a nanocomposites gas barrier film to the device. The device lifetime was consequently improved by 336%.

Silica–polystyrene (Si–PS) nanocomposite latex particles were prepared by emulsion polymerization using Hwangtoh clay as the silica source and blending with polyethylene terephthalate (PET) by melt extrusion. The Hwangtoh clay was mechanically grounded as nanoscale. XRD measurements showed more crystallized Hwangtoh clay in nano-dimension than that of raw material with crystallite sizes (t) of 108.52 and 126.7 nm, respectively. SEM (scanning electron microscope) measurements showed that the dispersed Si–PS hybrid nanocomposite had a D h of ~350 nm within the PET matrix. FTIR (Fourier transform infrared spectroscopy) measurements exhibited the characteristic absorption peaks of Si–O–Si stretching vibrations and Al–O–Si bending vibrations from both the Si–PS hybrid structure and PET/Si–PS composite. X-ray diffraction (XRD) measurements exhibited a characteristic Si diffraction peak of 2θ value at 25° and 29°, both from Si–PS hybrid nanoparticles and PET/Si–PS composites. The blending of PET with a Si–PS nanocomposite was determined by XPS (X-ray photoelectron spectroscopy) analysis, which showed three distinctive peaks representing the interatomic bonding of carbon. In XPS measurements, the decomposition of the Si 2p core peak demonstrated that the Si atom from Hwangtoh clay is composed of four chemical states such as Si0, Si+ (Si2O), Si2+ (SiO), and Si3+ (Si2O3). Our results provide evidence of the successful encapsulation of silicate from Hwangtoh clay in a PS shell, and further blending with PET by the melting extrusion method.

We analyze the movement of particles in an electric paper that consists of upper and lower electrodes. Particles inserted in a fluid move under the influence of an electric field when voltage is applied to the electrodes. The movement of particles is determined by the intensity of the electric field, the viscosity of the fluid, and the of the particles. Each factor has an impact on the independent particles. Considering these factors, we analyze the characteristics of the particles' movements. We analyze the behavior of the electric paper with experiments based on Stokes' Law.

The preparation of a hybrid dielectric film was carried out by blending sol–gel-derived sodium beta alumina (SBA) and poly(4-vinylphenol) (PVP) to enhance the capacitance of a gate dielectric film. PVP-SBA was cured at a temperature sufficiently low enough to apply to a plastic substrate, while maintaining good electrical properties and uniformity. Addition of sol–gel-derived SBA improved the film density, resulting in good PVP-SBA thermal stability. The prepared PVP-SBA was used for high-performance aqueous solution-based ZnO transistors at 200 °C.

Titanium dioxide (TiO2) nanoparticles were encapsulated with polystyrene (PS)-based copolymeric materials for an electrophoretic display application. This coating process was performed in order to improve the dispersion stability of electrophoretic pigment particles in a dielectric medium and to reduce the density mismatch between TiO2 and the dielectric medium. The characteristics of polymer-coated TiO2 nanoparticles of the density, chemical structure, particle size, shape, and morphology, were examined respectively by FT-IR, thermogravimetric analysis, particle size analysis, and SEM. Additionally, the electrophoretic mobility of the fabricated nanoparticles with a charge control agent was determined by measurements of the zeta potential.

Turbulent drag reduction (DR) efficacy of ionic poly(acrylic acid) and sodium dodecyl sulfate (SDS) complex system regarding polymer–surfactant interaction was examined under a turbulent flow in a rotating disk apparatus, in which the DR efficacy indicates how the torque is being reduced with a tiny amount of additives under a turbulent flow at a fixed rotational speed. Both addition of SDS and effect of pH on the ionic polymer were found to increase the polymer chain dimensions via a conformational structural change, thus enhancing the DR efficacy. Polymer–surfactant system also shows that there exists a critical polymer concentration at which the drag reduction becomes a maximum, and then above the critical concentration, the DR efficacy decreases more rapidly than that of pure polymeric systems. The dependence of drag reduction on the turbulent strength from the rotation speed change is also observed that the drag reduction increases with the increase of rotation speed regardless of polymer and surfactant concentration, implying that the complex interactions between the polymer and the surfactant molecules plays a critical role.