References of "Dabrowski, R."
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See detailAntiferroelectric liquid crystals with induced intermediate polar phases and the effects of doping with carbon nanotubes
Lagerwall, Jan UL; Dabrowski, R.; Scalia, G.

in Journal of Non-Crystalline Solids (2007), 353(47-51), 4411-4417

By mixing a commercial broad-temperature-range nematic liquid crystal mixture with a single-component antiferroelectric chiral smectic exhibiting two different chiral smectic-C-type phases as only ... [more ▼]

By mixing a commercial broad-temperature-range nematic liquid crystal mixture with a single-component antiferroelectric chiral smectic exhibiting two different chiral smectic-C-type phases as only mesophases, we have induced three phases which appear in neither of the two components; the paraelectric SmA* phase and the so-called intermediate phases SmC􏰀b and SmC􏰀c, antiferroelectric and heli- electric in nature, respectively. The generation of the two latter phases in mixtures where one component is an essentially non-chiral nematic is highly unexpected, since these phases are generally linked to high degree of smectic order and/or strong chiral interactions. It is probably made possible through microphase segregation driven by the incompatibility of the fluorinated tail of the smectic compo- nent with the non-fluorinated constituents of the nematic mixture. We also doped the nematic with single-wall carbon nanotubes (SWCNTs) before adding it to the smectic at the same concentration, allowing us to study the effect of SWCNTs on antiferroelectric liquid crystals. Although the final SWCNT concentration was very small (0.002 wt%) the phase sequence was radically altered, the ordin- ary SmC* phase now being present all the way between SmA* and crystallization, while all other variations of smectic-C-type order were suppressed. [less ▲]

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See detailElectrooptic and dielectric properties of new antiferroelectric liquid crystal mixtures
Andersson, G.; Dabrowski, R.; Drzewinski, W. et al

in Ferroelectrics (2000), 244

Two new antiferroelectric liquid crystal mixtures based on optically active hydroxyesters have been studied with respect to their electro-optic and dielectric behavior. The mixtures exhibit only a SmA ... [more ▼]

Two new antiferroelectric liquid crystal mixtures based on optically active hydroxyesters have been studied with respect to their electro-optic and dielectric behavior. The mixtures exhibit only a SmA* phase above SmCa* and show a stable antiferroelectric order over a broad temperature range (≈100°C). Electro-optic as well as dielectric studies suggest that the SmCa*-SmA* transition is second order. In thin cells signs of a sur- face-induced SmC* phase has also been observed. We present the rele- vant characteristics for three different electro-optic modes which could be exploited in these materials, including the very fast linear mode for sub-threshold voltages. [less ▲]

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See detailAntiferroelectric liquid crystals with 45° tilt - a new class of promising electro-optic materials
D’havé, K.; Dahlgren, A; Rudquist, Per et al

in Ferroelectrics (2000), 244

Antiferroelectric liquid crystals with a tilt angle of 45 degrees have very interesting optical properties, which seem to have been overlooked so far perhaps because such materials have hardly been ... [more ▼]

Antiferroelectric liquid crystals with a tilt angle of 45 degrees have very interesting optical properties, which seem to have been overlooked so far perhaps because such materials have hardly been available. We have prepared a four-component mixture of partially fluorinated compounds with a SmC/sub n/* phase in the interval between 27.4 degrees C and 121.6 degrees C, in which the tilt angle theta saturates at 45 degrees for T<or=80 degrees C, and we investigate the optical properties, theoretically and experimentally. One of the surprising features of 45 degree materials is that they permit a remarkably high contrast by virtue of an excellent dark-state, in spite of the fact that AFLC materials are notoriously difficult to align. This is because a 45 degrees AFLC turns out to be (negatively) uniaxial instead of biaxial. We describe these properties and propose a number of potentially interesting new applications, including a polarizer-free display mode and a three-level ``phase-only'' modulator. [less ▲]

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