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1H NMR study of molecular order and dynamics in CBC9CB Liquid Crystal (2019)
Journal Article
Aluculesei, A., Cachitas, H., Carvalho, J., Vaca Chavez, F., Figueirinhas, J. L., Sebastião, P. J., …Mehl, G. H. (2019). 1H NMR study of molecular order and dynamics in CBC9CB Liquid Crystal. Physical chemistry chemical physics : PCCP, 21(8), 4523-4537. https://doi.org/10.1039/c8cp06868b

Molecular order and dynamics of the CB-C9-CB liquid crystalline dimer exhibiting the nematic (N) and the twist bend nematic (Ntb) phases were investigated by proton NMR spectroscopy, using fields of 0.78T and 7.04T, and relaxometry. The first relaxom... Read More about 1H NMR study of molecular order and dynamics in CBC9CB Liquid Crystal.

Proton and Deuterium NMR study of the CBC9CB Dimer System (2019)
Journal Article
Carvalho, J., Cruz, C., Figueirinhas, J. L., Tamba, M., Kohlmeier, A., & Mehl, G. H. (2019). Proton and Deuterium NMR study of the CBC9CB Dimer System. Journal of Physical Chemistry B, 123(6), 1442-1451. https://doi.org/10.1021/acs.jpcb.8b11526

Using proton and deuterium NMR spectroscopy , this work provides a description of the molecular order of the mesogenic grops in both the Ntb and the classical nematic phase (N), of the liquid crystal dimer CB-C9CB. The proton NMR data were collected... Read More about Proton and Deuterium NMR study of the CBC9CB Dimer System.

EPR study of the polydomain structure of the twist-bend nematic phase of CB9CB in the bulk (2018)
Journal Article
Bacchiocchi, C., Tamba, M., Mehl, G. H., Arcioni, A., Miglioli, I., & Zannoni, C. (2018). EPR study of the polydomain structure of the twist-bend nematic phase of CB9CB in the bulk. Liquid crystals, 45(13-15), 2109-2120. https://doi.org/10.1080/02678292.2018.1501110

EPR spin probe spectra of the liquid crystal phases exhibited, in the bulk, by the 1″,9″-bis(4- cyanobiphenyl-4’-yl)nonane (CB9CB) bent-shape dimer showed that, on cooling from the isotropic phase, this material forms a uniaxial nematic phase with a... Read More about EPR study of the polydomain structure of the twist-bend nematic phase of CB9CB in the bulk.

Characterization of large tilt-angle flexoelectro-optic switching in chiral nematic liquid crystal devices (2018)
Journal Article
Wang, X., Fells, J. A. J., Welch, C., Tamba, M., Mehl, G. H., Morris, S. M., & Elston, S. J. (2019). Characterization of large tilt-angle flexoelectro-optic switching in chiral nematic liquid crystal devices. Liquid crystals, 46(3), 408-414. https://doi.org/10.1080/02678292.2018.1502822

The “flexoelastic ratio”, which is the ratio of the effective flexoelectric coefficient to the elastic coefficients, is commonly used to characterize the electro-optic behavior of chiral nematic liquid crystal (LC) devices that exhibit flexoelectro-o... Read More about Characterization of large tilt-angle flexoelectro-optic switching in chiral nematic liquid crystal devices.

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. doi: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), 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.

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. doi: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.

NMR study of a bimesogenic liquid crystal with two nematic phases (2015)
Journal Article
Burnell, E. E., Dong, R. Y., Kohlmeier, A., Tamba, M. G., Welch, C., & Mehl, G. H. (2015). NMR study of a bimesogenic liquid crystal with two nematic phases. Molecular crystals and liquid crystals, 610(1), 100-107. https://doi.org/10.1080/15421406.2015.1025211

Recent interest in bimesogenic liquid crystals showing two nematic phases has led us to investigate the nematic mean-field interactions in these nematic phases by using rigid solutes as probes. The nematic potential that is modelled by two independen... Read More about NMR study of a bimesogenic liquid crystal with two nematic phases.

A fibre forming smectic twist-bent liquid crystalline phase (2015)
Journal Article
Tamba, M. G., Salili, S. M., Zhang, C., Jákli, A., Mehl, G. H., Stannarius, R., & Eremin, A. (2015). A fibre forming smectic twist-bent liquid crystalline phase. RSC advances, 5(15), 11207-11211. doi:10.1039/c4ra14669g

We demonstrate the nanostructure and filament formation of a novel liquid crystal phase of a dimeric mesogen below the twist–bend nematic phase. The new fibre-forming phase is distinguished by a short-correlated smectic order combined with an additio... Read More about A fibre forming smectic twist-bent liquid crystalline phase.

Flexoelectric behavior of bimesogenic liquid crystals in the nematic phase-observation of a new self-assembly pattern at the twist-bend nematic and the nematic interface (2014)
Journal Article
Balachandran, R., Panov, V. P., Panarin, Y. P., Vij, J. K., Tamba, M. G., Mehl, G. H., & Song, J. K. (2014). Flexoelectric behavior of bimesogenic liquid crystals in the nematic phase-observation of a new self-assembly pattern at the twist-bend nematic and the nematic interface. Journal of materials chemistry. publ. by The Royal Society of Chemistry. C, Materials for optical and electronic devices /, 2(38), 8179-8184. doi:10.1039/c4tc01043d

Flexoelectric properties - the effective flexoelectric coefficient and flexoelectric polarization - are investigated for a bimesogenic liquid crystal CBC11CB with a twist bend nematic phase (Ntb). Results show that the effective flexoelectric coeffic... Read More about Flexoelectric behavior of bimesogenic liquid crystals in the nematic phase-observation of a new self-assembly pattern at the twist-bend nematic and the nematic interface.

The design and investigation of nanocomposites containing dimeric nematogens and liquid crystal gold nanoparticles with plasmonic properties showing a nematic-nematic phase transition (Nᵤ-Nₓ/Ntb) (2014)
Journal Article
Tamba, M., Yu, C. H., Tang, B. J., Welch, C., Kohlmeier, A., Schubert, C. P., & Mehl, G. H. (2014). The design and investigation of nanocomposites containing dimeric nematogens and liquid crystal gold nanoparticles with plasmonic properties showing a nematic-nematic phase transition (Nᵤ-Nₓ/Ntb). Materials, 7(5), (3494-3511). doi:10.3390/ma7053494. ISSN 1996-1944

The construction of liquid crystal compositions consisting of the dimeric liquid crystal, CB_C9_CB (cyanobiphenyl dimer = 1",9"-bis(4-cyanobiphenyl-4'-yl)nonane), and the range of nematic systems is explored. The materials include a laterally functio... Read More about The design and investigation of nanocomposites containing dimeric nematogens and liquid crystal gold nanoparticles with plasmonic properties showing a nematic-nematic phase transition (Nᵤ-Nₓ/Ntb).

Nematic twist-bend phase with nanoscale modulation of molecular orientation (2013)
Journal Article
Borshch, V., Kim, Y. -., Xiang, J., Gao, M., Jákli, A., Panov, V. P., …Lavrentovich, O. D. (2013). Nematic twist-bend phase with nanoscale modulation of molecular orientation. Nature communications, 4, https://doi.org/10.1038/ncomms3635

A state of matter in which molecules show a long-range orientational order and no positional order is called a nematic liquid crystal. The best known and most widely used (for example, in modern displays) is the uniaxial nematic, with the rod-like mo... Read More about Nematic twist-bend phase with nanoscale modulation of molecular orientation.

Design, synthesis, and characterization of mesogenic amine-capped nematic gold nanoparticles with surface-enhanced plasmonic resonances (2012)
Journal Article
Yu, C. H., Schubert, C. P. J., Welch, C., Tang, B. J., Tamba, M. G., & Mehl, G. H. (2012). Design, synthesis, and characterization of mesogenic amine-capped nematic gold nanoparticles with surface-enhanced plasmonic resonances. Journal of the American Chemical Society, 134(11), (5076-5079). doi:10.1021/ja300492d. ISSN 0002-7863

The use of the liquid-crystalline state to control the assembly of large (>5 nm) gold nanoparticles (NPs) is of considerable interest because of the promise of novel metamaterial properties of such systems. Here we report on a new approach for the pr... Read More about Design, synthesis, and characterization of mesogenic amine-capped nematic gold nanoparticles with surface-enhanced plasmonic resonances.

Spontaneous periodic deformations in nonchiral planar-aligned bimesogens with a nematic-nematic transition and a negative elastic constant (2010)
Journal Article
Panov, V. P., Nagaraj, M., Vij, J. K., Panarin, Y. P., Kohlmeier, A., Tamba, M. G., …Mehl, G. H. (2010). Spontaneous periodic deformations in nonchiral planar-aligned bimesogens with a nematic-nematic transition and a negative elastic constant. Physical review letters, 105(16), doi:10.1103/PhysRevLett.105.167801

Hydrocarbon linked mesogenic dimers are found to exhibit an additional nematic phase below the conventional uniaxial nematic phase as confirmed by x-ray diffraction. The phase produces unusual periodic stripe domains in planar cells. The stripes are... Read More about Spontaneous periodic deformations in nonchiral planar-aligned bimesogens with a nematic-nematic transition and a negative elastic constant.