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, doi: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

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. (in press). Proton and Deuterium NMR study of the CBC9CB Dimer System. Journal of Physical Chemistry B, doi: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

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. doi: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

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. (2018). Characterization of large tilt-angle flexoelectro-optic switching in chiral nematic liquid crystal devices. Liquid crystals, 1-7. doi: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

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

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. doi: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

Anomalous increase in nematic-isotropic transition temperature in dimer molecules induced by magnetic field (2016)
Journal Article
(2016). Anomalous increase in nematic-isotropic transition temperature in dimer molecules induced by magnetic field. Physical review letters, 116(21-27 May), doi: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

Second harmonic light scattering induced by defects in the twist-bend nematic phase of liquid crystal dimers (2016)
Journal Article
Shamid, S. M., Pardaev, S. A., Tamba, M. G., Mehl, G. H., Gleeson, J. T., Allender, D. W., …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. ISSN 1744-683X

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

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. doi: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

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., …Zhang, C. (2015). A fibre forming smectic twist-bent liquid crystalline phase. RSC advances, 5(15), (11207-11211). doi:10.1039/c4ra14669g. ISSN 2046-2069

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

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., …Vij, J. (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. ISSN 2050-7526

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

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
Yu, C. H., Tamba, M., Tang, B. J., Schubert, C. P., Mehl, G. H., Welch, C., …Tang, B. J. (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

Nematic twist-bend phase with nanoscale modulation of molecular orientation (2013)
Journal Article
Mehl, G., Lavrentovich, O. D., Borshch, V., Mehl, G. H., Gao, M., Tamba, M. G., …Borshch, V. (2013). Nematic twist-bend phase with nanoscale modulation of molecular orientation. Nature communications, 4, doi: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

Spontaneous periodic deformations in nonchiral planar-aligned bimesogens with a nematic-nematic transition and a negative elastic constant (2010)
Journal Article
Panarin, Y. P., Panov, V. P., Vij, J. K., Kohlmeier, A., Tamba, M. G., Lewis, R. A., …Vij, J. (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. ISSN 0031-9007

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