All Outputs (84)

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.

Sound absorption of porous cement composites: effects of the porosity and the pore size (2015)
Journal Article
Rutkevičius, M., Austin, Z., Chalk, B., Mehl, G. H., Qin, Q., Rubini, P. A., Stoyanov, S. D., & Paunov, V. N. (2015). Sound absorption of porous cement composites: effects of the porosity and the pore size. Journal of materials science, 50(9), 3495-3503. https://doi.org/10.1007/s10853-015-8912-5

© 2015, Springer Science+Business Media New York. We prepared sound absorbing cement–hydrogel composites using a hydrogel slurry templating technique. We air-dried the wet cement composites containing a varying percentage and size of entrapped hydrog... Read More about Sound absorption of porous cement composites: effects of the porosity and the pore size.

Do the short helices exist in the nematic TB phase? (2015)
Journal Article
Górecka, E., Salamończyk, M., Zep, A., Pociecha, D., Welch, C., Ahmed, Z., & Mehl, G. H. (2015). Do the short helices exist in the nematic TB phase?. Liquid crystals, 42(1), 1-7. https://doi.org/10.1080/02678292.2014.984646

Dimeric compounds forming twist-bend nematic, Ntb, phase show unusual optical textures related to the formation of arrays of focal conic defects (FCDs). Some of the focal conics exhibit submicron internal structure with 8 nm periodicity, which is ver... Read More about Do the short helices exist in the nematic TB phase?.

Synthesis and photochromic properties of a bis(diarylethene)-naphthopyran hybrid (2014)
Journal Article
Erko, F. G., Cseh, L., Berthet, J., Mehl, G. H., & Delbaere, S. (2015). Synthesis and photochromic properties of a bis(diarylethene)-naphthopyran hybrid. Dyes and pigments : an international journal, 115(April), 102-109. https://doi.org/10.1016/j.dyepig.2014.12.015

The synthesis and photochromic properties of a triphotochromic molecule consisting of one naphthopyran flanked by two diarylethene units investigated by UV-Visible and NMR spectroscopies are reported. Six different states resulting from the open/clos... Read More about Synthesis and photochromic properties of a bis(diarylethene)-naphthopyran hybrid.

Correction: 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). Correction: 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 C, 2(47), 10217. https://doi.org/10.1039/c4tc90153c

On the structure of the Nx phase of symmetric dimers: inferences from NMR (2014)
Journal Article
Hoffmann, A., Vanakaras, A. G., Kohlmeier, A., Mehl, G., & Photinos, D. J. (2015). On the structure of the Nx phase of symmetric dimers: inferences from NMR. Soft matter, 11(5), 850-855. https://doi.org/10.1039/c4sm02480j

NMR measurements on a selectively deuterated liquid crystal dimer CB-C9-CB, exhibiting two nematic phases, show that the molecules in the lower temperature nematic phase, NX, experience a chiral environment and are ordered about a uniformly oriented... Read More about On the structure of the Nx phase of symmetric dimers: inferences from NMR.

Fabrication of salt–hydrogel marbles and hollow-shell microcapsules by an aerosol gelation technique (2014)
Journal Article
Rutkevičius, M., Mehl, G. H., Petkov, J. T., Stoyanov, S. D., & Paunov, V. N. (2015). Fabrication of salt–hydrogel marbles and hollow-shell microcapsules by an aerosol gelation technique. Journal of Materials Chemistry B, 3(1), 82-89. https://doi.org/10.1039/c4tb01443j

We designed a new method for preparation of liquid marbles by using hydrophilic particles. Salt–hydrogel marbles were prepared by atomising droplets of hydrogel solution in a cold air column followed by rolling of the collected hydrogel microbeads in... Read More about Fabrication of salt–hydrogel marbles and hollow-shell microcapsules by an aerosol gelation technique.

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 C, 2(38), 8179-8184. https://doi.org/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.-G., 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. https://doi.org/10.3390/ma7053494

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).

Surface alignment, anchoring transitions, optical properties, and topological defects in the thermotropic nematic phase of organo-siloxane tetrapodes (2013)
Journal Article
Kim, Y.-K., Senyuk, B., Shin, S.-T., Kohlmeier, A., Mehl, G. H., & Lavrentovich, O. D. (2014). Surface alignment, anchoring transitions, optical properties, and topological defects in the thermotropic nematic phase of organo-siloxane tetrapodes. Molecular crystals and liquid crystals, 540(1), 20-41. https://doi.org/10.1039/C3SM52249K

We address the status of oxadiazole mesogens, C7 and C12, reported to show the biaxial nematic phase, by exploring material aspects (chemical stability, surface anchoring, optical and dielectric properties, topological defects) linked to the type of... Read More about Surface alignment, anchoring transitions, optical properties, and topological defects in the thermotropic nematic phase of organo-siloxane tetrapodes.

Nematic twist-bend phase with nanoscale modulation of molecular orientation (2013)
Journal Article
Borshch, V., Kim, Y. .-K., Xiang, J., Gao, M., Jákli, A., Panov, V. P., Vij, J. K., Imrie, C. T., Tamba, M. G., Mehl, G. H., & Lavrentovich, O. D. (2013). Nematic twist-bend phase with nanoscale modulation of molecular orientation. Nature communications, 4, Article ARTN 2635. 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.

Sound absorption properties of porous composites fabricated by a hydrogel templating technique (2013)
Journal Article
Rutkevicius, M., Mehl, G. H., Paunov, V. N., Qin, Q., Rubini, P. A., Stoyanov, S. D., & Petkov, J. (2013). Sound absorption properties of porous composites fabricated by a hydrogel templating technique. Journal of Materials Research, 28(17), 2409-2414. https://doi.org/10.1557/jmr.2013.194

We have used a hydrogel templating technique followed by the subsequent evaporation of water present to fabricate porous cement and porous PDMS composites, and we have analyzed their sound absorption properties. All experiments were carried out with... Read More about Sound absorption properties of porous composites fabricated by a hydrogel templating technique.

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. https://doi.org/10.1021/ja300492d

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.

Electrochemistry of organometallic lyotropic chromonic liquid crystals (2012)
Journal Article
Halls, J. E., Bourne, R. W., Wright, K. J., Partington, L. I., Tamba, M. G., Zhou, Y., Ramakrishnappa, T., Mehl, G. H., Kelly, S. M., & Wadhawan, J. D. (2012). Electrochemistry of organometallic lyotropic chromonic liquid crystals. Electrochemistry communications, 19(1), 50-54. https://doi.org/10.1016/j.elecom.2012.02.032

Two aqueous lyotropic chromonic liquid crystals made from nickel(II) or copper(II) phthalocyananine tetrasulfonic acid tetrasodium salt are prepared with characterisation through optical polarising microscopy, X-ray diffraction and conductivity. Thes... Read More about Electrochemistry of organometallic lyotropic chromonic liquid crystals.

Fabrication of novel lightweight composites by a hydrogel templating technique (2012)
Journal Article
Rutkevicius, M., Munusami, S. K., Watson, Z., Field, A. D., Salt, M., Stoyanov, S. D., Petkov, J., Mehl, G., & Paunov, V. N. (2012). Fabrication of novel lightweight composites by a hydrogel templating technique. Materials research bulletin, 47(4), 980-986. https://doi.org/10.1016/j.materresbull.2012.01.014

A non-conventional way of preparation of lightweight porous materials by templating hydrogels with a range of hydrophilic and hydrophobic scaffolding materials was explored. Sub-millimetre hydrogel slurries of polyacrylamide and gellan gum were templ... Read More about Fabrication of novel lightweight composites by a hydrogel templating technique.

Addressing fluorescence and liquid crystal behaviour in multi-mesogenic BODIPY materials (2011)
Journal Article
Benstead, M., Rosser, G. A., Beeby, A., Mehl, G. H., & Boyle, R. W. (2011). Addressing fluorescence and liquid crystal behaviour in multi-mesogenic BODIPY materials. New journal of chemistry = Nouveau journal de chimie, 35(7), 1410-1417. https://doi.org/10.1039/c0nj00990c

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 liqui... Read More about Addressing fluorescence and liquid crystal behaviour in multi-mesogenic BODIPY materials.

4,4′-Difluoro-4-bora-3a,4a-diaza-s-indacenes (BODIPYs) as components of novel light active materials (2011)
Journal Article
Benstead, M., Mehl, G. H., & Boyle, R. W. (2011). 4,4′-Difluoro-4-bora-3a,4a-diaza-s-indacenes (BODIPYs) as components of novel light active materials. Tetrahedron, 67(20), 3573-3601. https://doi.org/10.1016/j.tet.2011.03.028

Applications of BODIPY fluorophores as components of light active materials are reviewed.

Mesogenic BODIPYs: An investigation of the correlation between liquid crystalline behaviour and fluorescence intensity (2011)
Journal Article
Benstead, M., Beeby, A., Rosser, G. A., Mehl, G. H., & Boyle, R. W. (2011). Mesogenic BODIPYs: An investigation of the correlation between liquid crystalline behaviour and fluorescence intensity. Photochemical & photobiological sciences : an international journal, 10(6), 992-999. https://doi.org/10.1039/c0pp00388c

A series of mesogenic molecules based on the 4,4¢-di?uoro-3a,4a-diaza-s-indacene (BODIPY) ?uorophore have been synthesised and characterised. Each compound consists of one mesogenic unit, based on a cyanobiphenyl core, and one ?uorophore, of varying... Read More about Mesogenic BODIPYs: An investigation of the correlation between liquid crystalline behaviour and fluorescence intensity.

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., Lewis, R. A., & 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), Article ARTN 167801. https://doi.org/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.

Bridging the visible: the modulation of the absorption by more than 450 nm (2010)
Journal Article
Delbaere, S., Vermeersch, G., Frigoli, M., & Mehl, G. H. (2010). Bridging the visible: the modulation of the absorption by more than 450 nm. Organic Letters, 12(18), 4090-4093. https://doi.org/10.1021/ol101672v

The coexistence of 18 isomers, identified by NMR spectroscopy and gathered into six states with very different absorption properties, is observed upon irradiation with selective wavelengths of a triphotochromic system joining two naphthopyran entitie... Read More about Bridging the visible: the modulation of the absorption by more than 450 nm.