An anomalous electrokinetic dispersion after contraction of carbon nanotube (CNT) cluster suspended in a vertically aligned nematic liquid crystal (LC) cell is demonstrated. CNT aggregates were firstly aligned toward the field line by dielectrophoretic (DEP) torque and secondly they were elongated above a certain threshold field due to interaction between the induced dipole moment of CNTs and external ac electric field. Below a certain breakdown field, the original morphology of the CNT aggregates was restored after the removal of the field where the elongation was fully reversible. Above breakdown electric field, CNT aggregates were ruptured and fragmented into small pieces and consequently CNTs were well dispersed in LC medium.

Unusual double four-lobe nematic liquid crystal (LC) textures were observed in the carbon nanotube (CNT)-doped nematic LC under electric field. Through the electro-optical studies in a wide range of vertical electric fields in the direction of the long axis of the LC molecules, it was realized that the double four-lobe nematic LC textures were formed in the range of 120 to 160 V(rms) at 1 Hz. The formation of these unusual double four-lobe nematic LC textures could originate from the electric field-induced movement of CNTs and the subsequently frustrated reorientation of LCs.

A reflective display device based on electrowetting technology exhibits high reflection index over 40% and contrast ratio over 15 (conventional paper has reflection index of 60% and contrast index of 15). In addition to the attractive optical properties, this technology manifests a fast video response rate (<10 ms) and colour conversion factor of 67% which is four times higher than standard electrophoretic displays. These factors show that electrowetting technology is a strong alternative to electrophoretic technique which enables reflective displays available to the e-reader market. This technology offers advantages of insensitivity to cellgap variations and thus can be used to create electronic paper with excellent video capability at low cost. In this review we present the working principle, fabrication procedure and electro-optic response study of electrowetting display. Different challenges still to be overcome also have been discussed in detail.

Electrowetting is a new class of reflective display based on electric field controlled movement of oil/water interface across a hydrophobic layer. The focus of this paper is to fabricate electrowetting cells on a rough hydrophobic surface and to study its effect on kinetics of electrowetting. The surface roughening found effective in two ways in the design and operation of the electrowetting device: (i) It enhances the coating of photoresist (PR) on the hydrophobic surface, which is normally difficult due to low surface energy of Teflon and (ii) the roughness changes the contact angle of the liquid (oil), which in turn changes the electro-optic switching behavior of the device. The kinetics of optical switch was checked by calculating theoretically the white area fraction (WA%), which is a measure of optical switching in electrowetting display by changing the roughness of the hydrophobic surface. The present study showed that the optical performance found to increase with the increase of roughness of the hydrophobic surface.