Spontaneous Formation of Quasi-Bookshelf Layer Structure in New Ferroelectric Liquid Crystals Derived from a Naphthalene Ring

Takanishi, Yoichi; Ouchi, Yukio; Takezoe, Hideo; Fukuda, Atuso; Mochizuki, Ayako; Nakatsuka, Masakatsu

doi:10.1143/jjap.29.l984

Cited by 73 publications

(35 citation statements)

References 16 publications

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“…Recently, it has been found that there exist a number of smectic C * materials with different molecular structure (see, for example, Refs. [4,[6][7][8][9]) with anomalously weak layer contraction in the SmC phase. In fact, different materials are characterized by varying the degree of contraction below the SmA−SmC phase transition, and the majority of SmC liquid crystals correspond to the intermediate cases between strong and anomalously weak layer contraction.…”

Section: Introductionmentioning

confidence: 99%

Molecular theory of the tilting transition in smectic liquid crystals with weak layer contraction and diffused cone orientational distribution

Osipov

Paja̧k

2012

Phys. Rev. E

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A molecular field theory of the smectic-A-smectic-C transition has been developed for smectics with a diffused cone orientational distribution of molecules (volcano-like distribution function) in the smectic-A phase and anomalously weak layer contraction in the smectic-C phase. Orientational order parameters and smectic layer spacing have been calculated numerically as functions of temperature and compared with the results obtained using a model with a standard Maier-Saupe-type distribution function that has been considered before. A molecular theory of the electroclinic effect in chiral smectics has also been developed using the recently proposed simple biaxial interaction potential. A comparison has been made between the absolute values and temperature variations of the electroclinic coefficient obtained using the volcano model, the model with Maier-Saupe-type distribution, and the orthodox cone model proposed by de Vries. It has been shown that the model with a conventional "sugar loaf" type orientational distribution function in the smectic-A phase is sufficient to describe the main properties of smectics with anomalously weak layer contraction.

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Section: Introductionmentioning

confidence: 99%

Molecular theory of the tilting transition in smectic liquid crystals with weak layer contraction and diffused cone orientational distribution

Osipov

Paja̧k

2012

Phys. Rev. E

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“…The increase of the smectic layer spacing with lowering temperature not only in SmC Ã A but also in SmC Ã has been observed in several compounds and mixtures, although detailed study has not been carried out as yet. [47][48][49][50][51][52][53][54] This means that the relative displacements of molecules along their long axes or the layer undulational fluctuations as the pretransitional effect may play an important role in the temperature variation of the smectic layer spacing. In other words, we can insist on the importance of the other transition from SmC Ã /SmC Ã A to the hexatic or crystalline phase than the one from SmA to SmC Ã /SmC Ã A .…”

Section: Liquid Crystals 873mentioning

confidence: 99%

Renewed focus on the small temperature change of smectic layer spacing in ferroelectric and antiferroelectric LCs

et al. 2015

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We aim at becoming released from the invisible hand of de Vries scenario that a small temperature change in the smectic layer spacing must be caused by 'the far-fetched orientational distribution called the de Vries diffused cone' or 'the in-layer directors statically tilted and randomly distributed around the smectic layer normal'. First, we show in a prototypal compound MC513 that all the unusual properties suggesting the revival of a de Vries-type SmA-SmC Ã transition can be explained by ordinary SmA emergence just below the isotropic phase only in a narrow temperature range. Second, we take up the unconventional molecular structure of TSiKN65, thus far regarded as a typical de Vries material; the core part makes a large angle of β c ,30 with respect to the average molecular long axis. We insist that a slight change in β c can explain almost all the unusual properties without taking account of the de Vries scenario. Last but not least is a practical point of view. During a thermal shock cyclic reliability test between −20°C and 60°C in prototyping antiferroelectric liquid crystal displays (AFLCDs), DENSO noticed the importance of the transition from SmC Ã A to the hexatic or crystalline phase; the cell quality critically depends on the layer spacing change in the lower-temperature part of SmC Ã A . We point out that the relative displacements of molecules along their long axes and hence the layer undulational fluctuations play an important role in addition to the director tilting ones.

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“…A possible solution for this problem can be liquid crystalline materials with a de Vries-type phase transition, in which the transition happens with a negligible layer shrinkage. [14][15][16] In recent years, several such liquid crystalline materials have been reported, some of which contain a siloxane backbone.…”

Section: -6mentioning

confidence: 99%

Cyclic Co-oligomeric Ferroelectric Liquid Crystals with Fast Switching Properties, Wide SmC^Temperature Range and de Vries-type SmA^-SmC^*Transition

Park¹,

Cho²,

Yoon³

et al. 2011

Bulletin of the Korean Chemical Society

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We have synthesized and characterized the first cyclic co-oligomeric ferroelectric liquid crystals (FLCs) based on cyclic siloxanes and found that the co-oligomer containing two different mesogenic units exhibits SmC* mesophase over a wide temperature range from 65 o C to 135 o C, much wider than those of the monomer counterparts and the cyclic homo-oligomers. The cyclic co-oligomeric liquid crystal readily filled the display cell and exhibited fast switching times in the range of 4 ms to 6 ms over the entire SmC* phase. Moreover, the practical absence of layer shrinkage, attributed to de Vries-type transition, shows an additional significant advanage for cyclic co-oligomeric FLCs in LCD applications.

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Spontaneous Formation of Quasi-Bookshelf Layer Structure in New Ferroelectric Liquid Crystals Derived from a Naphthalene Ring

Cited by 73 publications

References 16 publications

Molecular theory of the tilting transition in smectic liquid crystals with weak layer contraction and diffused cone orientational distribution

Molecular theory of the tilting transition in smectic liquid crystals with weak layer contraction and diffused cone orientational distribution

Renewed focus on the small temperature change of smectic layer spacing in ferroelectric and antiferroelectric LCs

Cyclic Co-oligomeric Ferroelectric Liquid Crystals with Fast Switching Properties, Wide SmC^Temperature Range and de Vries-type SmA^-SmC^*Transition

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Spontaneous Formation of Quasi-Bookshelf Layer Structure in New Ferroelectric Liquid Crystals Derived from a Naphthalene Ring

Cited by 73 publications

References 16 publications

Molecular theory of the tilting transition in smectic liquid crystals with weak layer contraction and diffused cone orientational distribution

Molecular theory of the tilting transition in smectic liquid crystals with weak layer contraction and diffused cone orientational distribution

Renewed focus on the small temperature change of smectic layer spacing in ferroelectric and antiferroelectric LCs

Cyclic Co-oligomeric Ferroelectric Liquid Crystals with Fast Switching Properties, Wide SmC*Temperature Range and de Vries-type SmA*-SmC*Transition

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Product

Resources

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Cyclic Co-oligomeric Ferroelectric Liquid Crystals with Fast Switching Properties, Wide SmC^Temperature Range and de Vries-type SmA^-SmC^*Transition