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Characterization of the Submicrometer Hierarchy Levels in the Twist-Bend Nematic Phase with Nanometric Helices via Photopolymerization. Explanation for the Sign Reversal in the Polar Response (2017)
Journal Article
Panov, V. P., Sreenilayam, S. P., Panarin, Y. P., Vij, J. K., Welch, C. J., & Mehl, G. H. (2017). Characterization of the Submicrometer Hierarchy Levels in the Twist-Bend Nematic Phase with Nanometric Helices via Photopolymerization. Explanation for the Sign Reversal in the Polar Response. Nano Letters, 17(12), 7515-7519. https://doi.org/10.1021/acs.nanolett.7b03441

Photopolymerization of a reactive mesogen mixed with a mesogenic dimer, shown to exhibit the twist-bend nematic phase (NTB), reveals the complex structure of the self-deformation patterns observed in planar cells. The polymerized reactive mesogen ret... Read More about Characterization of the Submicrometer Hierarchy Levels in the Twist-Bend Nematic Phase with Nanometric Helices via Photopolymerization. Explanation for the Sign Reversal in the Polar Response.

Molecular organization in the twist–bend nematic phase by resonant X-ray scattering at the Se K-edge and by SAXS, WAXS and GIXRD (2017)
Journal Article
Stevenson, W. D., Ahmed, Z., Zeng, X. B., Welch, C., Ungar, G., & Mehl, G. H. (2017). Molecular organization in the twist–bend nematic phase by resonant X-ray scattering at the Se K-edge and by SAXS, WAXS and GIXRD. Physical chemistry chemical physics : PCCP, 19(21), 13449-13454. https://doi.org/10.1039/c7cp01404j

© the Owner Societies 2017. Using a magnetically aligned liquid crystal mixture containing a novel Se-labelled dimer and the difluoroterphenyl dimer DTC5C7, the twist-bend nematic phase (N tb ) was studied by the resonant scattering of hard X-rays an... Read More about Molecular organization in the twist–bend nematic phase by resonant X-ray scattering at the Se K-edge and by SAXS, WAXS and GIXRD.

Twist-bend nematic phase in cyanobiphenyls and difluoroterphenyls bimesogens (2016)
Journal Article
Panov, V. P., Vij, J. K., & Mehl, G. H. (2017). Twist-bend nematic phase in cyanobiphenyls and difluoroterphenyls bimesogens. Liquid crystals, 44(1), 147-159. https://doi.org/10.1080/02678292.2016.1254289

The paper reviews assignment of the low-temperature nematic phase observed in simple bimesogenic or dimeric systems based on cyanobiphenyls and difluoroterphenyls to the twist-bend nematic phase, NTB, using a range of experimental techniques. These i... Read More about Twist-bend nematic phase in cyanobiphenyls and difluoroterphenyls bimesogens.

Light scattering study of the “pseudo-layer” compression elastic constant in a twist-bend nematic liquid crystal (2016)
Journal Article
Parsouzi, Z., Pardaev, S. A., Welch, C., Ahmed, Z., Mehl, G. H., Baldwin, A. R., …Sprunt, S. (2016). Light scattering study of the “pseudo-layer” compression elastic constant in a twist-bend nematic liquid crystal. Physical chemistry chemical physics : PCCP, 18(46), 31645-31652. https://doi.org/10.1039/C6CP06292J

The nematic twist-bend (TB) phase, exhibited by certain achiral thermotropic liquid crystalline (LC) dimers, features a nanometer-scale, heliconical rotation of the average molecular long axis (director) with equally probable left- and right-handed d... Read More about Light scattering study of the “pseudo-layer” compression elastic constant in a twist-bend nematic liquid crystal.

Comparative analysis of anisotropic material properties of uniaxial nematics formed by flexible dimers and rod-like monomers (2016)
Journal Article
Cukrov, G., Mosaddeghian Golestani, Y., Xiang, J., Nastishin, Y. A., Ahmed, Z., Welch, C., …Lavrentovich, O. D. (2017). Comparative analysis of anisotropic material properties of uniaxial nematics formed by flexible dimers and rod-like monomers. Liquid crystals, 44(1), 219-231. https://doi.org/10.1080/02678292.2016.1240248

We report temperature dependencies of material properties such as dielectric anisotropy, birefringence, splay (K₁₁), twist (K₂₂), and bend (K₃₃) elastic constants of the uniaxial nematic (N) phase formed by flexible dimers of DTC5C9 and compare their... Read More about Comparative analysis of anisotropic material properties of uniaxial nematics formed by flexible dimers and rod-like monomers.

Director configuration in the twist-bend nematic phase of CB11CB (2016)
Journal Article
Miglioli, I., Bacchiocchi, C., Arcioni, A., Kohlmeier, A., Mehl, G. H., & Zannoni, C. (2016). Director configuration in the twist-bend nematic phase of CB11CB. Journal of Materials Chemistry C, 4(41), 9887-9896. https://doi.org/10.1039/c6tc03246j

The director distribution in the nematic phases exhibited by the 100,1100-bis(4-cyanobiphenyl-40-yl)undecane (CB11CB) liquid crystal has been studied in the bulk with the EPR spin probe technique. EPR spectra confirmed the presence of an higher tempe... Read More about Director configuration in the twist-bend nematic phase of CB11CB.

Deuteron and proton NMR study of D₂, p-dichlorobenzene and 1,3,5-trichlorobenzene in bimesogenic liquid crystals with two nematic phases (2016)
Journal Article
Burnell, E. E., Ahmed, Z., Welch, C., Mehl, G. H., & Dong, R. Y. (2016). Deuteron and proton NMR study of D₂, p-dichlorobenzene and 1,3,5-trichlorobenzene in bimesogenic liquid crystals with two nematic phases. Chemical Physics Letters, 659, 48-54. https://doi.org/10.1016/j.cplett.2016.07.005

The solutes dideuterium, 1,3,5-trichlorobenzene and p-dichlorobenzene (pdcb) are co-dissolved in a 61/39 wt% mixture of CBC9CB/5CB, a bimesogenic liquid crystal with two nematic phases. NMR spectra are collected for each solute. The local electric fi... Read More about Deuteron and proton NMR study of D₂, p-dichlorobenzene and 1,3,5-trichlorobenzene in bimesogenic liquid crystals with two nematic phases.

Mesophase structure and behaviour in bulk and restricted geometry of a dimeric compound exhibiting a nematic-nematic transition (2016)
Journal Article
Sebastián, N., Tamba, M. G., Stannarius, R., de la Fuente, M. R., Salamonczyk, M., Cukrov, G., …Eremin, A. (2016). Mesophase structure and behaviour in bulk and restricted geometry of a dimeric compound exhibiting a nematic-nematic transition. Physical chemistry chemical physics : PCCP, 18(28), 19299-19308. https://doi.org/10.1039/c6cp03899a

We present structural studies of a dimeric compound composed of a central heptyl spacer linking two mesogens consisiting of terphenyl units at which two adjacent fluoro groups are attached to each central ring. The terminal rings are linked to pentyl... Read More about Mesophase structure and behaviour in bulk and restricted geometry of a dimeric compound exhibiting a nematic-nematic transition.

Fluctuation modes of a twist-bend nematic liquid crystal (2016)
Journal Article
Parsouzi, Z., Shamid, S. M., Borshch, V., Challa, P. K., Baldwin, A. R., Tamba, M. G., …Sprunt, S. (2016). Fluctuation modes of a twist-bend nematic liquid crystal. Physical Review X, 6(2), 021041-1-021041-16. https://doi.org/10.1103/PhysRevX.6.021041

We report a dynamic light-scattering study of the fluctuation modes in a thermotropic liquid crystalline mixture of monomer and dimer compounds that exhibits the twist-bend nematic (NTB) phase. The results reveal a spectrum of overdamped fluctuations... Read More about Fluctuation modes of a twist-bend nematic liquid crystal.

Anomalous increase in nematic-isotropic transition temperature in dimer molecules induced by magnetic field (2016)
Journal Article
Salili, S. M., Tamba, M. G., Sprunt, S. N., Welch, C., Mehl, G. H., Jákli, A., & Gleeson, J. T. (2016). Anomalous increase in nematic-isotropic transition temperature in dimer molecules induced by magnetic field. Physical review letters, 116(21-27 May), Article 217801. https://doi.org/10.1103/PhysRevLett.116.217801

We have determined the nematic-isotropic transition temperature as a function of applied magnetic field in three different thermotropic liquid crystalline dimers. These molecules are comprised of two rigid calamitic moieties joined end to end by flex... Read More about Anomalous increase in nematic-isotropic transition temperature in dimer molecules induced by magnetic field.

Added alkane allows thermal thinning of supramolecular columns by forming superlattice - an X-ray and neutron study (2016)
Journal Article
Yen, M. H., Chaiprapa, J., Zeng, X., Liu, Y., Cseh, L., Mehl, G. H., & Ungar, G. (2016). Added alkane allows thermal thinning of supramolecular columns by forming superlattice - an X-ray and neutron study. Journal of the American Chemical Society, 138(18), 5757-5760. https://doi.org/10.1021/jacs.6b01172

We report a columnar superlattice formed by blends of dendron-like Li 3,4,5-tris(n-alkoxy)benzoates with n-alkanes. Without the alkane, the wedge-shaped molecules form liquid crystal columns with 3 dendrons in a supramolecular disk. The same structur... Read More about Added alkane allows thermal thinning of supramolecular columns by forming superlattice - an X-ray and neutron study.

Second harmonic light scattering induced by defects in the twist-bend nematic phase of liquid crystal dimers (2016)
Journal Article
Pardaev, S. A., Shamid, S. M., Tamba, M. G., Welch, C., Mehl, G. H., Gleeson, J. T., …Sprunt, S. (2016). Second harmonic light scattering induced by defects in the twist-bend nematic phase of liquid crystal dimers. Soft matter, 12(19), 4472-4482. https://doi.org/10.1039/c6sm00585c

The nematic twist-bend (NTB) phase, exhibited by certain thermotropic liquid crystalline (LC) dimers, represents a new orientationally ordered mesophase -- the first distinct nematic variant discovered in many years. The NTB phase is distinguished by... Read More about Second harmonic light scattering induced by defects in the twist-bend nematic phase of liquid crystal dimers.

Similarities and differences between molecular order in the nematic and twist-bend nematic phases of a symmetric liquid crystal dimer (2016)
Journal Article
Emsley, J. W., Lelli, M., Joy, H., Tamba, M. G., & Mehl, G. H. (2016). Similarities and differences between molecular order in the nematic and twist-bend nematic phases of a symmetric liquid crystal dimer. Physical chemistry chemical physics : PCCP, 18(14), 9419-9430. https://doi.org/10.1039/c5cp07304a

The order parameter, Szz, where z is the para axis of the difluoroterphenyl groups in DTC5C9, have been obtained from chemical shift anisotropies measured by ¹³C – {¹1H} NMR experiments at temperatures throughout the nematic, NU, and twist-bend nemat... Read More about Similarities and differences between molecular order in the nematic and twist-bend nematic phases of a symmetric liquid crystal dimer.

Thermal optical non-linearity of nematic mesophase enhanced by gold nanoparticles – an experimental and numerical investigation (2016)
Journal Article
Kurochkin, O., Murugesan, Y. K., Bennett, T. P., D'Alessandro, G., Reznikov, Y., Tang, B. J., …Kaczmarek, M. (2016). Thermal optical non-linearity of nematic mesophase enhanced by gold nanoparticles – an experimental and numerical investigation. Physical chemistry chemical physics : PCCP, 18(16), 11503-11512. https://doi.org/10.1039/c6cp00116e

In this work the mechanisms leading to the enhancement of optical nonlinearity of nematic liquid crystalline material through localized heating by doping the liquid crystals (LCs) with gold nanoparticles (GNPs) are investigated. We present some exper... Read More about Thermal optical non-linearity of nematic mesophase enhanced by gold nanoparticles – an experimental and numerical investigation.

Synthesis and characterization of gold nanoparticles functionalized with calamitic mesogens (2016)
Journal Article
Cseh, L., & Mehl, G. H. (2016). Synthesis and characterization of gold nanoparticles functionalized with calamitic mesogens. 00 Journal not listed, 61(2), 125-130

(Image presented) Liquid-crystalline nanoparticles represent an exciting class of new materials for a variety of potential applications. By combining supramolecular ordering with the fluid properties of the liquid-crystalline state, these materials o... Read More about Synthesis and characterization of gold nanoparticles functionalized with calamitic mesogens.

The stabilisation of the Nx phase in mixtures (2016)
Journal Article
Ramou, E., Ahmed, Z., Welch, C., Karahaliou, P. K., & Mehl, G. H. (2016). The stabilisation of the Nx phase in mixtures. Soft matter, 12(3), 888-899. https://doi.org/10.1039/c5sm01961c

The phase behaviour of mixtures between two symmetric dimers, CBC9CB and the ether-linked analogue CBOC9OCB was investigated by Polarizing Optical Microscopy (POM), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD) studies. The dime... Read More about The stabilisation of the Nx phase in mixtures.

The design and investigation of the self-assembly of dimers with two nematic phases (2015)
Journal Article
Ahmed, Z., Welch, C., & Mehl, G. H. (2015). The design and investigation of the self-assembly of dimers with two nematic phases. RSC advances, 5(113), 93513-93521. https://doi.org/10.1039/c5ra18118f

A series of non-symmetric dimers were synthesised containing either cyanobiphenyl or difluoroterphenyl moieties on one side and a range of long, short, bent, polar or apolar mesogens on the other side of the molecules. The dielectric anisotropy of th... Read More about The design and investigation of the self-assembly of dimers with two nematic phases.

Helically twisted chiral arrays of gold nanoparticles coated with a cholesterol mesogen (2015)
Journal Article
Cseh, L., Mang, X., Zeng, X., Liu, F., Mehl, G., Ungar, G., & Siligardil, G. (2015). Helically twisted chiral arrays of gold nanoparticles coated with a cholesterol mesogen. Journal of the American Chemical Society, 137(40), 12736-12739. https://doi.org/10.1021/jacs.5b05059

© 2015 American Chemical Society. Gold nanoparticles have been prepared and surface-functionalized with a 1:1 molar mixture of a hexylthiol ligand and a chiral mesogenic ligand consisting of a cholesterylbenzoate attached via an undecylthiol spacer.... Read More about Helically twisted chiral arrays of gold nanoparticles coated with a cholesterol mesogen.

Mononuclear Cu(II) complexes of novel salicylidene Schiff bases: synthesis and mesogenic properties (2015)
Journal Article
Cretu, C., Cseh, L., Tang, B. J., Sasca, V., Badea, V., Szerb, E. I., …Costisor, O. (2015). Mononuclear Cu(II) complexes of novel salicylidene Schiff bases: synthesis and mesogenic properties. Liquid crystals, 42(8), 1139-1147. https://doi.org/10.1080/02678292.2015.1028491

Two new Schiff base ligands 1 and 2 (where 1 = 4-(2-hydroxybenzilidenamino)-phenyl-4-(decyloxy)-2-(pent-4-enyloxy)benzoate, 2 = 4-(4-(decyloxy)-2-hydroxybenziliden amino)-phenyl-4-(decyloxy)-2-(pent-4-enyloxy)benzoate) and their copper (Cu)(II) compl... Read More about Mononuclear Cu(II) complexes of novel salicylidene Schiff bases: synthesis and mesogenic properties.

Stabilised columnar mesophases formed by 1 : 1 mixtures of hexaalkoxytriphenylenes with a hexaphenyltriphenylene-based polymer (2015)
Journal Article
McLaren, S. R., Tate, D. J., Lozman, O. R., Mehl, G. H., & Bushby, R. J. (2015). Stabilised columnar mesophases formed by 1 : 1 mixtures of hexaalkoxytriphenylenes with a hexaphenyltriphenylene-based polymer. Journal of Materials Chemistry C, 3(22), 5754-5763. https://doi.org/10.1039/c5tc00661a

The synthesis is reported for a main chain polymer in which the repeat units are 2,3,6,7,10,11-hexaphenyltriphenylene moieties linked through flexible dodecyl chains. In compositions with a series of 2,3,6,7,10,11-hexakis(alkoxy)triphenylenes (HATn)... Read More about Stabilised columnar mesophases formed by 1 : 1 mixtures of hexaalkoxytriphenylenes with a hexaphenyltriphenylene-based polymer.