Electrically controlled light scattering from thermoreversible liquid-crystal gels

Abstract

Thermoreversible gels of the liquid-crystal LC-E7 with 1,3:2,4-Di-O-benzylidene-D-sorbitol ͑DBS͒ form white light-scattering films that are reversibly switchable to a clear state by ac electric fields. The light scattering by the gelled films is an intrinsic material property that originates in the phase diagram of the system displaying a monotectic-type equilibrium ͑''mesotectic''͒ among a liquid, a solid, and a mesophase at extremely low concentrations of DBS. Electro-optical characteristics and demonstrated viscoelastic behavior of the films produced indicate the applicability of DBS/ LC-E7 in large area scattering-based flat panel displays and projection systems.

Commentary on ‘Vaccines for preventing influenza in healthy children’, with responses from the review authors and from the editors of Evidence‐Based Child Health

“…Einige Gele des Typs I, die durch Zugabe kleiner Mengen (0.2–3.0 Gew.‐%) nanometergroßer selbstorganisierter Fasern zu Flüssigkristallen erzeugt wurden, sind lichtstreuende elektrooptische Materialien 5. 302, 303 Flüssigkristalline Polydomänen werden effektiv durch zufällige Dispersion selbstorganisierter Fasern aus Gelbildnern in nematischen Flüssigkristallen erhalten. Diese Strukturen bilden lichtstreuende, trübe Zustände, die beim Anlegen eines elektrischen Felds transparent werden (Abbildung 31).…”

The Function of Self-Assembled Polyfluorene-Based π-Conjugated Supramolecular Structures Formed in Twisted Nematic Liquid Crystals

“…In recent years, the fibrous supramolecular polymer network combining with the electrically switchable liquid crystal (LC) system have been developed as soft functional materials -LC physical gels [7][8][9][10]. The LC physical gels have been widely applied in various electro-optical devices, such as switchable scattering devices [11][12][13][14], LC semiconductors with high mobility [15,16], and stabilization of the orientation of ferroelectric LCs [17], etc. In particular, fast-response switching in twisted nematic (TN) cells based on the aid of fibrous polymer network have attracted more and more interests for their potential for improving the quality of LC displays (LCDs) [18][19][20].…”

Photomodulated Electro-optical Response in Self-Supporting Liquid Crystalline Physical Gels

“…LC physical gels which consist of the LC as a host and a low-molecular-weight compound as a gelator which can be interconnected into networks by noncovalent interactions with a content less than 10 wt %. , The LC in the gels remains the fast response to external fields and shows excellent electro-optical properties, whereas the formation of anisotropic phase-separated structures leads to the introduction of specific functions and the enhancement of the properties . Because the phase diagram of the gels displayed a monotectic-type equilibrium among a liquid, a solid, and a mesophase at extremely low concentration of gelator, the white light-scattering films of the LC physical gels could be switched to a clear state by an alternating current . In comparison with pure LC, fast electrical responses including the response time under low driving voltage were achieved with a low content of l -isoleucine derivative because of the anisotropical structures of LC in the gels. , Through electric-induced LC orientation, the photoluminescence and optical transmittance could be repeatedly switched without fatigue for the gels of a gelator showing aggregation-induced enhanced emission in LC BL006 .…”