Key Engineering Materials Vols. 428-429

Abstract: Ultraviolet curable sealant was synthesized by polymerizing epoxy resin with acrylic acid in the presence of catalyst N,N-dimethylbenzylamine. The synthesized ultraviolet-curable sealant could be solidified upon exposure to 365 nm ultraviolet irradiation for 8 seconds. The optical, mechanical and thermal properties of the ultraviolet-cured sealant were investigated with ultraviolet-visible spectrometer, tensile machine and differential scanning calorimetry, respectively. Our results demonstrated that the transparent and thermally stable sealant was strong enough for liquid crystal display panels.

Abstract: Calcium carbonate is often used as an efficient antacid that absorbs and neutralizes stomach acid while providing calcium for healthy bones. Taking advantage of the lack of adverse side effects of calcium, new drug delivery systems consisting of drug-supported spherical microparticles are being developed. We have reported in our previous studies that a natural process producing calcium carbonate microparticles can be found during avian development. These natural systems provide inspiration for designing more efficient microparticle facilitated drug-delivery systems. In this study, the formation and re-absorption of calcium carbonate crystals were tracked during Gallina N. meleagris embryogenesis and early postnatal development. The study demonstrated that the formation of calcium carbonate microparticles, as calcium is transferred from the eggshell into the egg sac, is a process of calcium preservation. X-ray diffraction showed that calcium carbonate crystal is mainly preserved in the vaterite isoform. Calcium incorporated into the yolk sac during this process can be easily assimilated as necessary during postnatal development. Eons of evolution have yielded a calcium preservation process that produces an iso-form of crystalline calcium most readily absorbed by the organism. Our previous results indicate that this biological system is likely a lyotropic process, the method that is currently being used for the production of microparticle drug delivery systems. In this work, our data suggests that calcium carbonate crystal can also initiate its crystallization from the center of liquid crystal, recognizable by a chimeric thermal phase transition. Our work provides valuable information for designing more efficient microparticle for drug-delivery.

Abstract: Micro/nanoscale liquid crystal (LC) droplets are dispersed within polymer matrix, known as polymer-dispersed liquid crystals (PDLCs). LC molecules can be reoriented under an applied voltage, which makes PDLC-based devices have wide applications in optical communications, integrated optics, and panel displays, etc. In this paper, we summarized our work on holographic PDLC (H-PDLC) devices including variable attenuators, dynamic gain equalizers and focus-switchable lenses. More importantly, a specially designed H-PDLC chopper array was demonstrated, which will be applied in the new-born frequency division multiplexed high-speed fluorescence confocal microscope system.

Abstract: We present an easy way to make liquid crystal cells for laboratory uses. It is demonstrated that a homemade LC cell can be made out of two pieces of ITO glasses, a tiny amount of glue and four tiny pieces of thin Mylar films as spacers. The flatness of the thin panels is evaluated with an ultraviolet-visible spectrometer by measuring the transmission spectra for a series spots on the homemade LC cell. Tests of our homemade LC cells filled with a banana-shaped LC show that the quality of our homemade LC cell is good enough for regular laboratory tests of newly synthesized LC compounds.

Abstract: A self-collimation splitting sensor truncated in a two-dimensional (2D) photonic crystal has been proposed and demonstrated theoretically. Intensity of transmitted light and reflected light, which varies with the width of the splitter, is detected at two output ports. Calculation results validated by the 2D finite-difference time-domain technique show that with the increase of width, the transmittivity decreases while the reflectivity increases and their summation decreases. Considering the trade-off between the sensitivity of the optical detector and the loss of power, including the difficulty of fabrication, the width of 0.4a is meet for the sensor. The simulated relative intensity monotonously increases from 1.63 to 2.94 nonlinearly.

Abstract: The manufacture of display device is a complex technology. To reach the flexible display like E-paper, many manufacture process such as driving electrode circuit and transistor must be combined with printing technology. From the information reported, the application of gravure prints technology in organic electronics; off-set printing in EMI film and screen technology in circuit are summarized. The study was more about ink jet print technology. It was described that ink jet was used in OLED (Organic light-emitting diode), OTFT (organic thin film transistor), polymer solar cell/ Flexible organic photovoltaic cell and so on. An OE-A (organic electronics application) roadmap for the charge carrier mobility of semiconductors for organic electronics applications was given. To achieve the printed circuit, the nano silver conductive ink was applied and the ink jet circuit surface was tested by microscopy, the conductive and flexible silver film was with many advantages than screen circuit. It was concluded that the printing electronic will play important roll in the display development.

Abstract: According to the manufacturing procedure of liquid crystals modules (LCM), several display distortions of LCM, such as S line distortion, G line distortion, line short-circuit and cs-open are introduced. Combined with its internal structure and its working principle, key causes and repair methods of these distortions are focused on. The pass rate of the product is improved. A foundation has been laid on research in automated diagnosing systems which based on image processing and circuit parameter diagnosing technology.

Abstract: In the presence of the aqueous solution of ammonia, tetraethyl orthosilicate (TEOS) was hydrolyzed in the mixture of ethyl alcohol and water with the results of silica spacers. The spacer morphology and size distribution of the synthesized silica spacers were characterized with scanning electron microcopy and laser light scattering spectroscopy, respectively. Our results demonstrated that the synthesized silica spacers were monodispersed and were in perfect spherical shape with their sizes of about 0.7 m in diameter. The correlation between the spacer sizes and the amount of ammonia catalyst was examined, and the spacer sizes of the silica spacers strongly depended on the temperature of chemical reaction and the amount of catalyst. The diameter of silica spacers could be well controlled by controlling the amount of ammonia catalyst, and uniformly distributed silica spacers were produced. Behavior of the miscibility of the silica spacers with a nematic liquid crystal was examined.

Abstract: A new effective fabrication module was developed to mediate the problem of the low yield of Indium-tin-oxide (ITO) nanostructures deposition uses micro electroremoval technology and a design of twins-cylinder tool as a precision etching process to remove the defective Indium-tin-oxide (ITO) from the optical PET diaphragm surfaces of digital-paper displays. For the removal-process, a small gap width between the negative electrode and the workpiece (optical PET diaphragm) surface corresponds to a higher removal rate for the ITO. A small diameter of the anode or a small diameter of the cathode of the twins-cylinder tool provides large electric current density and takes less time for the same amount (20 nm) of ITO removal. High rotational speed of the twins-cylinder tool the discharge mobility and results in improving the removal effect. Providing enough electrical power can uses fast feed rate of the optical PET diaphragm combined with a fast removal rate for ITO. With increasing in current rating, pulsed direct current can improve the effect of dregs discharge and is advantageous to associate with the fast feed rate of the optical PET diaphragm. By establishing a recycling process using the ultra-precise removal of thin-film nanostructures, through the micro electroremoval and the twins-cylinder electrodes requires only a short period of time to remove the ITO thin-film easily and cleanly. The optoelectronic semiconductor industry can effectively recycle defective products, minimizing both production costs and pollution.

Abstract: A series of shape memorized liquid crystalline epoxides with different length of lateral substituents were prepared with several kinds of hardener. The dynamic mechanical analysis and the sharp memory properties of the resulted LC epoxy resins were studied by POM, WAXD, DSC and DMA. The results showed that the modulus in the rubbery region (ER) of the LC epoxides decreases as the length of lateral alkyl groups increases. And the shape memory properties were strongly impacted not only by the length of lateral substituents, but also by the kinds of hardener. The recovering speeds of the shape-memory liquid crystalline epoxides decrease as the increasing length of lateral alkyl groups. And recovering speeds of LC epoxides cured with aromatic amine (DDM) are faster than that of LC epoxides cured with anhydride (THHPA). The local ordered structures and the lateral substituents played an important role in shape memory effects.