Glassy nematic phase

Miniewicz, A. Samoc, A. Samoc, M. Kaszynski, P. Observation of second harmonic generation in an oriented glassy nematic phase of a [BiqHio] derivative, J. Appl. Phys. 2007,102,033108. 

It is clear that the nematic phase exhibits a featureless Rayleigh wing and that several distinct solid phases can be formed depending on cooling rate [79]. This includes an apparently glassy phase. The vertical tick marks indicate the calculated frequencies of vibrational modes as obtained from density functional methods. 

Sorai, M. and Seki, S. Glassy liquid crystal of the the nematic phase of N-(o-Hydroxy-p-methoxybenzylidene)-p-butylaniline. Bull. Chem. Soc. Japan 44, 2887 (1971)... 

Cr Cub, Cubv d E G HT Iso Isore l LamN LaniSm/col Lamsm/dis LC LT M N/N Rp Rh Rsi SmA Crystalline solid Spheroidic (micellar) cubic phase Bicontinuous cubic phase Layer periodicity Crystalline E phase Glassy state High temperature phase Isotropic liquid Re-entrant isotropic phase Molecular length Laminated nematic phase Correlated laminated smectic phase Non-correlated laminated smectic phase Liquid crystal/Liquid crystalline Low temperature phase Unknown mesophase Nematic phase/Chiral nematic Phase Perfluoroalkyl chain Alkyl chain Carbosilane chain Smectic A phase (nontilted smectic phase)... 

Figure 7 (left) The electric field dependence of the time-ofiflight hole mobility for poly(9.9-dioctylfluorene) films. The open circles are data for a film prepared by spin coating. The filled circles are for a sample spin coated on a rubbed polyimide orientation layer, annealed in the nematic phase and then quenched to form a glassy film. 

Drozd-Rzoska, A. (2009) Glassy dynamics of liquid ciystalline 4 - -pentyl-4-cyanobiphenyl (5CB) in the isotropic and supercooled nematic phase, J. Chem. Phys. 130, 234910... 

The pitch of the helix for compound 42 was found to be approximately 0.2-0.3 xm, thus the material selectively reflects visible light over a wide temperature range. Moreover, the pitch is relatively temperature insensitive thus the material can be used in large area non-absorbing polarizers, or in optical notch filters or reflectors. In addition, in the glassy state the helical macrostructure of the chiral nematic phases is retained, thus similar applications are possible. 

Like the other side-chain LCPs described in the previous section, these materials also oflfer the possibility of locking the chiral nematic phase into the glassy state by rapid cooling to temperatures below Tg. This leads to a preservation of the structure and its reflected color. With suitable systems, the process can thus be used to produce stable and light-fast monochromatic films. 

G glassy state, Dl discotic lamella phase, Nd discotic nematic phase, Colhi hexagonal columnar phase, I isotropic phase... 

Crystallographic and optical studies show that these threads are almost perfect monocrystals. Here is a useful tool for study of structures. It may also be possible to apply this property of columnar phases to the problem of extruding threads with very high degrees of orientation, which could then be trapped in a glassy phase. The well known product Kevlar has a nematic phase and we might wonder if it does not also attain a columnar phase under extrusion. 

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