Merck liquid crystals

S. Naemura, T. Oyama, H. Plach, G. Weber and B. Scheuble, E. Merck, Liquid Crystal Seminar Data. 

A nematic liquid crystal cell, based on Merck Licrilite E202, was used in these experiments. The rod like liquid crystal molecules preferentially aligned themselves with each other and to an alignment surface in the liquid crystal device. Any birefringence. An, was given as the difference between the two orthogonal refractive indices. As a consequence, any resulting... 

Electronic chemicals (see Section 11.4) provide another illustrative example of the difference between fine and specialty chemicals Merck KGaA produces a range of individual fine chemicals as active substances for liqnid crystals in a modern multipurpose plant in Darmstadt, Germany. An example is (trans,trans)-A-[difluoromethoxy)-3,5-difluorophenyl]-4 -propyl-l,l -bicyclohexyl. Merck ships the active ingredients to its secondary plants in Japan, Sonth Korea, and Taiwan, where they are compounded into liquid crystal formulations. These specialties have to comply with stringent use-related specifications (electrical and color properties, etc.) of the Asian producers of consumer electronics such as cellular phones, DVD players, and flat-screen TV sets. 

Electronic chemicals Liquid crystals Licristal Trifluoromethoxyphenyl derivatives (e.g.) Merck KGaA, Germany... 

Merck KGaA Fine chemicals for liquid crystals soaring... 

Yoshida et al. recently disclosed an alternative method that allowed them to produce stable suspensions of gold nanoparticles (1-2 nm in diameter) in nematic liquid crystals [315]. They used a simple sputter deposition process, which allowed them to prepare thin liquid crystal films of well-dispersed gold nanoparticles in both 5CB and E47 (available from Merck) with a nanoparticle size depending on the used nematic liquid crystal. Unfortunately, the authors did not provide any details on whether the nanoparticles were capped with a ligand or bare, non-coated particles, which makes it difficult to assess and compare the reported thermal as well as electro-optic data. However, very similar effects were found as a result of nanoparticle doping, including lower nematic-to-isotropic phase transition temperatures compared to the used pure nematics as well as 10% lower threshold voltages at nanoparticle concentrations below 1 wt% [315]. 

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 predicted boom in LCD TVs has been made possible by a new generation of liquid crystals. Three of Merck s scientists are at the very forefront of this development Melanie Klasen-Memmer, Kazuaki Tarumi, and Matthias Bremer. 

For liquid crystals, the following factors have proved critical in Merck s success ... 

Over a century ago, Professor Otto Lehmann of the University of Karlsruhe - who is acknowledged as the pioneer of liquid crystal technology - disagreed with the scientific establishment about the existence of the liquid crystalline state of aggregation. Lehmann turned to Merck. He asked the company to supply him (and others) with liquid crystalline compounds so that he could clarify what no amount of theoretical debate could resolve. This was Merck s first foray into the LC business - although there was no actual business at this stage. Nevertheless, it was already well known that Merck supplied products of the highest purity, which allowed results to be replicated accurately. 

However, it was not until 1967 that the technology was woken from its slumber by Americans James Fergason and George Heilmeier. These two developed the first technical applications of liquid crystals in thermography and the first liquid crystal displays Merck resumed its interest in liquid crystals, and the business began. 

Many at Merck were skeptical of this technology and sarcastic comments floated around, generally referring to superfluous crystals (in German, jlussig means liquid, but ubeifliissig means superfluous) but despite this internal resistance, our liquid crystal pioneers remained resolutely positive. 

Kazuaki Tarumi, one of the liquid crystal research/physics team at Merck, is particularly aware of Ignorance , without which he might have taken seriously the many arguments against his research project and never achieved the goal. 

Merck s LC division has a particular challenge as it has to operate in the context of today s fast moving electronics industry. Displays and related technologies are being developed ever faster, which means that more efficient liquid crystal mixtures are needed ever more rapidly. 

This is demonstrated by the success story of Merck s liquid crystals, high-tech chemicals with unique properties. Discovered over a century ago by German scientists, they caused controversy in the scientific community at first, but - with the help of Merck s highest-purity substances - liquid crystals were eventually accepted as a fourth state of aggregation. 

Dr. Werner Becker, Merck KGaA, Liquid Crystals Division, 64271 Darmstadt, Germany... 

MeOAn-ANI-3 NI in the nematic liquid crystal mixture E-7 (Merck) at two orientations of the liquid crystal director, L, taken 700 ns after a 420 nm laser pulse at 150 K. The narrow signal is an expansion of the radical pair signal, (b) Numerical differentiation of the B L L spectrum. 

Using 34, a Type I molecule, one can orient these molecules in liquid crystal (LC) phase such as a nematic ZLI-2452 (LC phase commercially available from Merck Co). Using polarized light, a different ratio D of the absorption E y and E is possible. The dichroic ratio... 

Table 3.1 Transition temperatures CC), dielectric anisotropy (As) and conductivity (Or cm ) for nematic liquid crystals (1-11) and a commercial mixture (Merck) designed for DSM-LCDs...

The log, lath-like molecular structure of most liquid crystalline compounds makes the cross-coupling protocol very important in syntheses [178,179]. The method based on arylboronic acids simplifies the procedure for liquid crystal materials of more complex substitution patterns [64,180,181] (Scheme 32). The synthesis of arylboronic acids via ortho-metalation of fiuoroarenes and the successive cross-coupling reaction readily extended the aryl units. The Pd/C-cat-alyzed reaction was also reported as an economical alternative [64]. Several liquid crystals having a biaryl unit are now an industrial process of Merck in Germany (ca. 3 tons/year) [182]. 

Table 4.10 Examples for the most commonly used dielectrically negative liquid crystals deriving their dipole moment from lateral difluorination. The virtual clearing points TNi.vin are extrapolated from the Merck mixture ZLI-4792, Af from ZLI-2857 [41].

A central part of the application-oriented evaluation of liquid crystals are so-called virtual clearing temperatures, electrooptic properties, and viscosities. These data are obtained by extrapolation from a standardized nematic host mixture. 7 Af, An, and jy are determined by linear extrapolation from a 10% iv/iv solution in the commercially available Merck mixture ZLI-4792 (Tfji = 92.8°C, Af = 5.27, An = 0.0964). For the pure substances the mesophases are identified by optical microscopy and the phase transition temperatures by differential scanning calorimetry (DSC). The transition temperatures in the tables are cited in °C, numbers in parentheses denote monotropic phase transitions which occur only on cooling the sample C = crystalline, S = smectic A, Sg = smectic B, S = smectic G, S> = unidentified smectic phase, N = nematic, I = isotropic. 

Merck KGaA Liquid Crystals Division Frankfurter Stralle 250 64293 Darmstadt Germany... 

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... 

Merck Ltd. Liquid Crystals Merck House Poole BH15 ITD U.K. Germany... 

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