- Aminoxyl radicals bearing a mesogenic core
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A series of aminoxyl radicals (nitronyl nitroxide or TEMPO) bearing biphenylcarbonitrile as a mesogenic core (2a-2c and 3a-3c) was prepared. Among them, unusual magnetic transition from the original Curie-Weiss phase to another magnetic phase well express
- Ikemoto, Hiroshi,Akutsu, Hiroki,Yamada, Jun-Ichi,Nakatsuji, Shin'Ichi
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Read Online
- Self-organisation through size-exclusion in soft materials
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A number of materials derived from 4-undecyloxy-4′-cyanobiphenyl but with varying terminal groups were prepared in order to better understand how such a group influences the type, and local structure of mesophases formed. Whereas electron poor terminal groups (fluoroaromatics and halogen atoms) were found to destabilise the smectic A phase through unfavourable electrostatic interactions, bulky silane, siloxane and hydrocarbon groups can be incorporated into the structure of the phase with only minor reductions in clearing point. An increase in the layer spacing of the smectic Ad phase in materials with bulky groups suggests that microphase segregation is not the driving force, but rather exists as a consequence of steric crowding at the smectic layer interface. Electrooptic studies reveal that 'carbosilane' end groups, such as tetramethyldisilapropane, are significantly more electrochemical stable than their siloxane counterparts whilst retaining their desirable thermal properties.
- Mandle, Richard J.,Davis, Edward J.,Voll, Constantin-Christian A.,Lewis, Daniel J.,Cowling, Stephen J.,Goodby, John W.
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supporting information
p. 2380 - 2388
(2015/04/14)
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- A synthetic strategy toward branched oligomesogenic phosphonic acids: Comparison of alternative pathways
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This work is devoted to the elaboration of a practical scheme for the synthesis of dendritic derivatives of gallic acid containing a carboxylate-ω-alkylphosphonic acid group and three terminal promesogenic substituents. Two synthetic strategies toward the
- Prodanov, Maksym F.,Vashchenko, Olga V.,Vashchenko, Valerii V.
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supporting information
p. 275 - 278
(2014/01/06)
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- Synthesis of inimers and hyperbranched polymers
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An inimer, and process for making same, having the following formula: wherein X=halogen, nitroxide, thioester; R═H or CH3; and R′=aliphatic, non-aliphatic, linear or branched, mesogenic, non mesogenic, chiral, achiral, hydrocarbon, non-hydrocarbon, selected from fluorocarbon, oligo(oxyethylene) and siloxane substituents, alkyl, aryl, mesogenic group, non-mesogenic group, aliphatic, non-aliphatic, siloxane, perfluoroalkyl, perfluoroaryl, or other fluorocarbon group, and polymers, and the process of making them, from the inimer.
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Page/Page column 17-18
(2013/09/12)
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- Addressing fluorescence and liquid crystal behaviour in multi-mesogenic BODIPY materials
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Two series of BODIPYs (4,4′-difluoro-3a,4a-diaza-s-indacene) bearing mesogenic substituents have been synthesised and their fluorescent and self-assembly behaviour has been observed and characterised. In order to induce a strong preference for liquid crys
- Benstead, Michael,Rosser, Geraldine A.,Beeby, Andrew,Mehl, Georg H.,Boyle, Ross W.
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supporting information; experimental part
p. 1410 - 1417
(2011/09/19)
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- Synthesis and characterization of light-driven dithienylcyclopentene switches with axial chirality
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Three new photochemically reversible but thermally stable dithienylcyclopentene switches with axial chirality were synthesized and characterized. All the compounds exhibited photochemically reversible isomerization with thermal stability between its open form and closed form in both organic solvent and liquid crystal host. Their photoresponsive behaviors in organic solvents were characterized by 1H NMR, UV-vis, and CD spectra. These chiral molecular switches were found not only to be able to act as a chiral dopant and induce a helical superstructure in an achiral liquid crystal host but also to be able to reversibly and dynamically tune the transmittance and reflection of the resulting chiral phase upon light irradiation. The helical twisting powers, transmittance, and reflection spectra of photoswitchable cholesteric LCs were measured. Dopant 1 exhibited an unusually high helical twisting power, which is significantly larger than those of the known chiral diarylethenes reported as chiral dopants so far.
- Li, Yannian,Urbas, Augustine,Li, Quan
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experimental part
p. 7148 - 7156
(2011/10/31)
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- Fluorocarbon and hydrocarbon end groups: Effects on mesomorphism and physical properties of smectic liquid crystals
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In this article we examine the effects of cyclohexane and perfluorocyclohexane being used as bulky end groups on the mesomorphism of classical smectic liquid crystal mesogens. The mesogen that is used in this work is typical of the MHPOBC family of materi
- Cowling, Stephen J.,Hall, Alan W.,Goodby, John W.
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scheme or table
p. 9031 - 9042
(2012/01/15)
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- Core chirality based tailoring of the liquid crystalline properties of supermolecular tetrapedes
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A series of novel supermolecular star-shaped tetrapede chiral liquid crystals (LCs), incorporating carbohydrates, methyl α-d-glucopyranoside or methyl α-d-mannopyranoside, as chiral cores surrounded by four cyanobiphenyl mesogenic groups linked by either C6 or C11 alkyl chain spacers, have been synthesised. These non-conventional thermotropic carbohydrate-based chiral liquid crystals exhibit chiral nematic and smectic A mesophases over broad temperature ranges. The mesomorphic properties were characterized by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). The effect of the flexible spacer length in addition to the stereogenic and conformational properties of the chiral cores is discussed.
- Belaissaoui, Abdelhak,Cowling, Stephen J.,Saez, Isabel M.,Goodby, John W.
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scheme or table
p. 1958 - 1963
(2011/10/31)
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- Tailor-designed polyphilic promotors for stabilizing dispersions of carbon nanotubes in liquid crystals
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We present a potent multifunctional molecular design concept for promoting the dispersion of carbon nanotubes (CNTs) in thermotropic liquid crystals (LCs), making CNT-in-LC dispersions of unprecedented stability possible and broadening the scope of potent
- Kuehnast, Martin,Tschierske, Carsten,Lagerwall, Jan
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supporting information; experimental part
p. 6989 - 6991
(2010/11/04)
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- Examination of the interlayer strength of smectic liquid crystals through the study of partially fluorinated and branched fluorinated end-groups
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Through the incorporation of partially fluorinated and branched fluorinated end-groups of ferroelectric liquid crystals we aimed to examine the effects on physico-chemical structures and properties, and electrical switching behaviour for a family of compo
- Cowling, Stephen J.,Hall, Alan W.,Goodby, John W.,Wang, Ying,Gleeson, Helen F.
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p. 2181 - 2191
(2007/10/03)
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- MATERIALS
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The present invention relates to a compound of the general structure of formula (I): X-Alkylene1-A-1-Alkylene2-A2-(Z1)x-B-(Z2)y-C-(Z3)z-A3/
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Page/Page column 13-14; 21-22
(2008/06/13)
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- A chiral electrooptic response in a racemic liquid crystal
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Over recent years, little attention has been paid to the electrooptic properties of racemic modifications of smectic liquid crystals, however, in this communication we report on a chiral response of a racemic modification to an applied electrical field wh
- Cowling, Stephen J.,Hall, Alan W.,Goodby, John W.
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p. 1546 - 1548
(2007/10/03)
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- Novel radical compounds bearing mesogenic cores with long alkyl substituents
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Series of aminoxyl radicals (TEMPO or nitronyl nitroxide radicals) bearing phenyl benzoate, troponoid, or biphenylcarbonitrile as mesogenic cores with long alkyl substituents were prepared. Although most aminoxyl radicals showed only weak antiferromagnetic interactions due probably to the remote spin centers as clarified by the X-ray analysis of 4a and no appreciable mesogenic phase was observed in each compound, an unusual magnetic transition from an original Curie-Weiss phase to another magnetic phase well-expressed by a singlet-triplet (ST) model was disclosed through the thermal transition in the 4′-undecyloxy-4-biphenylcarbonitrile derivative with oxocarbonyl-TEMPO 12b.
- Nakatsuji, Shin'ichi,Ikemoto, Hiroshi,Akutsu, Hiroki,Yamada, Jun-Ichi,Mori, Akira
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p. 1708 - 1714
(2007/10/03)
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- Styrene-containing mesogens. Part 1: Photopolymerisable nematic liquid crystals
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Several members of a novel series of styrene-containing liquid crystal monomers, based on the cyanobiphenyl mesogenic group, possess thermally stable nematic phases. These materials display a large odd-even effect, relating to the length of the flexible spacer between the styrene and cyanobiphenyl units, which is very similar to previously described liquid crystal 'dimers' composed of two cyanobiphenyl units. It is shown that styrene (i.e. 4-vinylphenoxy) is an excellent terminal group for cyanobiphenyl mesogens as compared to a number of other phenyloxy groups. In addition, a compatible bifunctional mesogenic crosslinker is described. Photopolymerisation of an aligned film of a low-melting eutectic mixture derived from these compounds is achieved using cationic initiation in aerobic conditions.
- Cook, Anthony,Badriya, Samer,Greenfield, Simon,McKeown, Neil B.
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p. 2675 - 2683
(2007/10/03)
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- Effect of Molecular Structure on Mesomorphism. 22. Liquid Crystalline 1-Alkanol Derivatives
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Several 1-alkanols having a mesogenic unit attached to the omega-carbon have been prepared.Many of these are liquid crystalline.The nematic mesophase is predominant for these materials.This is presumably due to intermolecular hydrogen-bonding between polar terminal groups such as cyano or nitro and the primary hydroxyl functionality of a proximal molecule.The resulting end-to-end association favors a nematic mesophase.
- Griffin, A. C.,Vaidya, S. R.
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