E7 liquid crystal

Novel, flexible, completely organic, polymer dispersed liquid crystal (PDLC) "light valves" were fabricated using two flat pieces of commercial overhead transparency substrates (Nashua j -20) coated with polypyrrole between which a film of commercial PDLC material (Norland Products Co. NOA 65 optical adhesive and BDH Ltd. E7 liquid crystal fluid together with EM. Ind. 15 micron polystyrene spacers) was sandwiched. The optical adhesive was polymerized by exposure to UV light. Thin conducting polypyrrole films of varying controllable thickness were deposited on the overhead transparency. 

Performance limits for fast scan multiplexed TN-LCDs are derived here. These limits were determined by means of computer calculations referenced to current experimental results as a baseline. Results of the calculations are summarized in Table 2. The baseline for the computations was the cell and material parameters corresponding to low tilt display cells using E7 liquid crystal and are given in the accompanying paper in this volume. ... 

As the baseline for our calculations described in the Appendix, we take the typical LCD cell configuration of thickness d=8 ym filled with E7 liquid crystal mixture with a cholesteric additive giving a natural cholesteric pitch P=40 ym. The boundary conditions imposed on the liquid crystal are total twist 0q=9O , pretilt ao=3 and strong surface anchoring. The polarizers are crossed and parallel to the nematic director at the neighboring liquid crystal surfaces. In calculations where the total twist... 

Chen et al. reported on a general approach by which the polarization of the emission from semiconductor nanorods can be manipulated by an external bias. In their device, the composite of a nematic liquid crystal mixture (E7, Merck) and nanorods (CdS) filled into an ITO-coated cell with an optimized concentration of one CdS nanorod per 1010 LC molecules was used to achieve the highest polarization ratio of the suspended nanorods [447, 448]. The nematic liquid crystal in this system acts as a solvent and media whose direction of alignment can be tuned by an applied electric field. Hence, the orientation of the CdS nanorods can be fine-tuned by an external bias because of the anchoring force between the liquid crystal... 

The linear dichroism of nickel(II), palladium(II) and zinc(II) complexes of mesomorphic 4-alkoxydithiobenzoic acids has been investigated in the commercial eutectic mixture of cyanobiphenyls and cyanoterphenyls, E7 (from Merck) for the palladium(II) complexes and in the commercial mixture of cyanobicyclohexanes, ZLI2830 (from Merck) for the nickel(II) and zinc(II) complexes (Figure 2.12).For the nickel(II) and palladium(II) complexes both a ligand-based transition and a charge-transfer band (MLCT) were observed, whereas only a ligand-based transition was present for the zinc(II) complexes. These complexes had a much lower solubility in the liquid crystal host matrix than the dithiolene... 

Van Deun et al. were the first to observe near-infrared luminescence from lanthanide-doped liquid crystal mixtures They studied the spectroscopic properties of the lanthanide(III) / -diketonate complexes [L (dbm)3(phen)], where Ln = neodymium, erbium, ytterbium, and dbm is dibenzoylmethane, in the liquid crystal MBBA. By incorporation of an erbium(III)-doped nematic liquid crystal (ErCls dissolved in E7) in the pores of microporous silicon, narrowing of the erbium(III) emission band in the near-infrared was observedJ Luminescent optically active liquid crystals were obtained by doping [Eu(tta)3-3H20] into a mixture of cho-lesteryl nonanoate, cholesteryl tetradecanoate and the ternary liquid crystal mixture ZLI1083 from MerckJ ... 

Fig. 2. Partial phase diagram of the binary mixture liquid crystal E7/silicone oil (Aldrich). is the E7 weight fraction. The Fig. shows an isotropic phase (1) above 60°C, a coexistence domain between an isotropic and a nematic phase (1+N) below 60°C, and a nematic phase (N) in the extreme right part of the diagram. The systems are quenched from the nematic domain to 20°C as indicated by the arrow...

The best geometrical parameters of periodic Si structures were theoretically estimated before the structure preparation [4]. Using the procedure described elsewhere [5], the grooved Si samples were created with lattice constant A=16, 8, and 4 pm, each sample with number of Si walls m=50 and the samples with A=24, 12, and 10 pm, m = 3 and 4. The lattice constant A may be written as A=Dsi + Dap. The Si structures were infiltrated by commercial nematic liquid crystal E7. 

Nematic ordering can be observed and quantified based on a change in a characteristic band of the liquid crystal. Moreover, the phase separation and the onset of nematic ordering can be temporarily resolved. The conversion at phase separation decreased strongly with an increase in liquid crystal content, while the conversion required for phase separation increased with increasing temperature. The fraction of liquid crystal present as nematic droplets and total fraction of nematic domains in NOA65 were quantified from changes in the vibrational spectrum of the liquid crystal (E7, which refers to the commercial label for the liquid crystal) (37). 

IR microspectroscopy was used to generate functional group images of liquid crystal(E7) droplets dispersed in poly-n-butyl methacrylate(PBMA). The spatial concentration fluctuations that occurred within the system were studied as a function of time. This approach was possible because spectral information could be obtained by focusing on regions of the order of tens of micrometers. The peak intensities were used as a measure of concentration of the components. The amount of liquid crystal dissolved in the polymer matrix determined the... 

Fig. 11.10 Kramers-Kronig relations (a) Qualitative spectra of absorbance of an isotropic liquid with admixture of a dye in the UV and visible range (above) and corresponding spectrum of the refraction index (below)-, (b) Experimental polarization spectra of absorption coefficient ajbs for a nematic liquid crystal E7 doped with a smtill amount of dye Chromene (upper plot) and corresponding spectra of the increment of refraction indices 5 for two polarizations calculated with Eq. (11.29) (lowerplot). For both plots symbols (e) and (o) mean linear polarizations parallel and perpendicular to the director...

To investigate the role of LCP in the composite on the electro-optical properties, PS[4BC/DM]s with the degree of polymerization of 12 and 40 were used as LCP. In order to investigate the role of LCD in the composite on the electro-optical effect, low molecular weight smectic LC, S2 was employed as a sample of composite in which any LCP was not included. S2 is a binary smectic mixture of low molecular weight liquid crystals as shown in Figure 1. The ionic impurities (Pt catalyst) of about 1000 ppm was added to S2 to unify the condition of electric current effect with the (PS[4BC/DM](n=12, 40)/E7) composites which contain about 1000 ppm of Pt catalyst. 

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