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Stable Amorphous Blue Phase Of Bent-Core Nematic Liquid Crystals Doped With A Chiral Material, Stefanie Taushanoff, Khoa Le, Jarrod Williams, Robert Twieg, B. Sadashiva, Hideo Takezoe, Antal Jakli
Stable Amorphous Blue Phase Of Bent-Core Nematic Liquid Crystals Doped With A Chiral Material, Stefanie Taushanoff, Khoa Le, Jarrod Williams, Robert Twieg, B. Sadashiva, Hideo Takezoe, Antal Jakli
Antal Jakli
We report an induction of the blue phase III (BPIII) at a relatively low and wide ( over 20 degrees C) temperature range in nematogenic achiral bent-core liquid crystals doped with a high twisting power chiral material. The pitch decreases with increasing chiral dopant ratio, and easily reaches the ultraviolet wavelength, so that completely dark texture is obtained under crossed polarizers. Electrooptical switching was achieved in a time range of a few to a few tens of milliseconds. We propose for the stabilization of BPIII that broad-temperature range smectic nano-clusters inhibit the long-range order of the double twisted helical structures, …
Odd-Even Effects In Bent-Core Compounds Containing Terminal N-Alkyl Carboxylate Groups, S. Umadevi, Antal Jakli, B. Sadashiva
Odd-Even Effects In Bent-Core Compounds Containing Terminal N-Alkyl Carboxylate Groups, S. Umadevi, Antal Jakli, B. Sadashiva
Antal Jakli
A homologous series of eleven five-ring symmetrical bent-core compounds containing terminal n-alkyl carboxylate groups were synthesized, characterized and their dielectric and electro-optical properties have been investigated. The lower homologues (n = 6-11) of the series show B-2 structures with an interesting odd-even effect concerning their local director tilt and polar arrangements. This odd-even effect probably is due to steric (entropic) reasons, which are not suppressed by the relatively low polar interaction. Three of the middle homologues display a B-7' phase, which is bistable and shows linear electro-optical switching with a transition to the chiral antiferroelectric smectic phase at a lower …
Bistable Linear Electro-Optical Switching In The B-7 ' Phase Of Novel Bent-Core, S. Umadevi, Antal Jakli, B. K. Sadashiva
Bistable Linear Electro-Optical Switching In The B-7 ' Phase Of Novel Bent-Core, S. Umadevi, Antal Jakli, B. K. Sadashiva
Antal Jakli
Three novel symmetrical bent-core compounds were synthesized where the terminal alkoxy linkages of the original bent-core inesogen forming a B-2 phase was converted to n-alkyl carboxylates. It is found that instead of the B-2 phase, all three compounds exhibit a transition between B-7' and B-2 mesophases. The physical and electro-optical properties have been investigated by polarizing optical microscopy, differential scanning calorimetry, X-ray diffraction and electric field experiments. The higher temperature B-7' phase has been shown to exhibit bistable but analogous linear electro-optical Switching Without,my observable polarization peak. We analyze two theoretical models and find that a local triclinic symmetry may …