Bistable state in polymer stabilized blue phase liquid crystal

Zheng, Zhigang; Zhang, Dan; Lin, Xiao-wen; Zhu, Ge; Hu, Wei; Shen, Dong; Lu, Yan‐qing

doi:10.1364/ome.2.001353

Cited by 6 publications

(3 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Wang et al reported the bistable states of BP I and BP II that found in BP LCs system, and their phase transition behaviors were also studied [27] . The PSBP bistability was also found [28] . Unlike conventional PSBP, which went from PSBP directly to field-induced vertical alignment (VA) when driven by saturated electric field, an intermediate chiral nematic phase was observed between the above two states when the applied field was increased slowly to the saturation.…”

mentioning

confidence: 85%

Brief review of recent research on blue phase liquid crystal materials and devices

Zheng¹,

Zhu²,

Sun³

et al. 2013

中国光学快报

View full text Add to dashboard Cite

Both polymer stabilization and bent-shaped molecule doping strategies are utilized to widen the blue phase range of liquid crystals. The molecular structures of compositions are optimized for high thermooptical and electro-optical performances. A low temperature applicable blue phase liquid crystal with suppressed hysteresis is achieved. The bistability of one blue phase liquid crystal is investigated. Based on these materials, fast tunable devices such as gratings with polarization insensitivity are designed and fabricated. The materials and device designs demonstrated here are suitable in wide applications requiring fast response time.OCIS codes: 160.3710, 050.1950, 160.4670. doi: 10.3788/COL201311.011601. It is well known that the nematic, smectic, and cholesteric are three typical phases of the conventional liquid crystals (LCs). The blue phase (BP) is also a special LC phase which normally exists in the materials with large twisted power. When such material is cooled down, many colorful platelet textures can be found in a very narrow temperature range (1-2 K) between the isotropy and chiral nematic phases, that is the BP [1] . Many theoretical analysis and experimental phenomenon have revealed that LC alignment in BP is complex and exotic. Not like the single twisted assembling in cholesteric phase, LC molecules are double twisted assembled in BP. The two twisted axes are crossed with each other and form the double twisted cylinders (DTCs). These DTCs can either exist in disordered distribution, exhibiting a fog-like texture (BP III), or self-assemble into three-dimensional (3D) crystals, showing colorful platelet textures (BP I and BP II) due to the selective Bragg reflections [2,3] . The unique structure of BP LC endows it with some interesting characteristics, such as optical isotropy at voltage off state, fast response time down to submillisecond, which are much benefit for the next generation of display and photonic devices [4−10] . Although BP LC was found a century ago, it was failed to be applied realistically for quite a long time due to its instinct problems, especially its narrow temperature range. Many efforts have been made to overcome this shortage. Some great improvements have been achieved during the last decade. The first promising wide temperature range BP was demonstrated by Kikuchi et al. [11] . They uniformly mixed acrylate based monomers into chiral nematic LCs, and then exposed the mixture under UV at BP state to polymerize the monomers. Finally, the BP was stabilized by polymer network, and the BP range was extended to over 60 • C. This is the so called polymer stabilized BP (PSBP). The mechanism of PSBP is that the polymer forms a stable 3D framework and stabilizes the defects in the frustration BP system. After this strategy was established, especially after Samsung exhibited the first BP LC display (LCD) at SID Display Week in Los Angeles, in 2008, more and more attentions had been attracted by the promising materials. Wu's group [12] has made great contributions to the impro...

show abstract

mentioning

confidence: 85%

Brief review of recent research on blue phase liquid crystal materials and devices

Zheng¹,

Zhu²,

Sun³

et al. 2013

中国光学快报

View full text Add to dashboard Cite

show abstract

“…[11][12][13][14][15][16][17][18][19][20][21][22] Among them, a polymer stabilized blue phase liquid crystal (PS-BPLC) is the most efficient method to stabilize BPs as polymer networks could concentrate in the isotropic defect core and localize the disclination core of the BP structure. 11,12 Besides polymer networks, molecular designs have been widely adopted as a method to stabilize BPs such as hydrogen bond molecules, 13 bimesogenic molecules, T-shaped molecules 15,16 and bent-core molecules. [17][18][19][20][21] Additionally, other methods like nanoparticles 22 have also been used to widen the temperature range of BPs.…”

Section: Introductionmentioning

confidence: 99%

Optically binary liquid crystalline blue phases induced by one-armed cholesterol-linked azobenzene molecules

Yin

Gao

et al. 2015

Soft Matter

View full text Add to dashboard Cite

A series of one-armed cholesterol-linked azobenzene molecules named CholXAzo with different spacers were synthesized, in which Chol6Azo was found to have induced blue phases (BPs) with a concentration of 4.0 wt%. Under irradiation of 385 nm UV light with a density of 15.0 mW cm(-2), photo-responsive behaviour of the 4.0 wt% Chol6Azo doped sample named B3 shows a sensitive temperature dependence, which means that at 38.0 °C a phase transition from BPs to the isotropic phase is induced; however, at 33.0 °C, this phase transition does not take place. Results from the research show that the optically binary phase transition behaviour of B3 is sensitive to the isomerization degree of Chol6Azo, which is closely related to the stability of the BP structure and there is a critical isomerization degree of 13.7% for the phase transition of the B3 liquid crystals. Further POM observation shows that the liquid crystal samples doped with different concentrations of Chol6Azo have an increasing transition temperature for photo-induced phase transition from the BP to the isotropic phase along with the increasing concentration of Chol6Azo, which are found to have the same changing tendency with phase transition temperature from the isotropic phase to BPs and a phase diagram is made to map the optically binary behaviour of Chol6Azo doped blue phase liquid crystals. At last, a simple pattern with the BP and the isotropic phase arranged at an interval was made in this optically binary liquid crystalline blue phase under a suitable photomask.

show abstract

“…Bistable liquid crystal display (BLCD) has attracted intensive attentions thanks to the feature of power required only in updating images while electrical field unneeded in maintaining off/on states [1][2][3][4][5][6][7]. Therefore it is quite suitable for displays that would not be frequently updated, such as electronic signage cards, e-books, and even large electronic billboards.…”

Section: Introductionmentioning

confidence: 99%

Large birefringence smectic-A liquid crystals for high contrast bistable displays

Ji¹,

Lei²,

Tang³

et al. 2015

Opt. Mater. Express

Self Cite

View full text Add to dashboard Cite

We developed two kinds of bistable smectic-A liquid crystal mixtures. Compared with traditional cyanobiphenyl and cyanoterphenyl derivatives, several changes have been made in molecular design: Isothiocyanato is used as a substitute for cyano to increase the optical anisotropy; fluoro groups are added on 3 and 5 positions of the isothiocyanato substituent terminal phenyl ring to increase both the dielectric anisotropy and eutectic property of the smectic mixture; derivatives of (4-isothiocyanatophenyl) pyridine are introduced to produce a wide smectic range. Thanks to above designs, the final smectic-A mixtures exhibit highly improved properties, such as higher contrast, lower operation voltages and wider temperature range. Based on the developed liquid crystals, electronic tags were also demonstrated, which exhibit reliable performance. This work reveals new insights for tailing liquid crystal molecules with bistability, which is extremely meaningful for the design and fabrication of green display devices.

show abstract

Bistable state in polymer stabilized blue phase liquid crystal

Cited by 6 publications

References 23 publications

Brief review of recent research on blue phase liquid crystal materials and devices

Brief review of recent research on blue phase liquid crystal materials and devices

Optically binary liquid crystalline blue phases induced by one-armed cholesterol-linked azobenzene molecules

Large birefringence smectic-A liquid crystals for high contrast bistable displays

Contact Info

Product

Resources

About