Outputs (14)

Deciphering helix assembly in the heliconical nematic phase via tender resonant X-ray scattering (2021)
Journal Article
Cao, Y., Feng, J., Nallapaneni, A., Arakawa, Y., Zhao, K., Zhang, H., Mehl, G. H., Zhu, C., & Liu, F. (2021). Deciphering helix assembly in the heliconical nematic phase via tender resonant X-ray scattering. Journal of Materials Chemistry C, 9(31), 10020-10028. https://doi.org/10.1039/d1tc02027g

Being a link between a uniaxial nematic and a chiral nematic, the twist bend nematic (NTB) has been an intriguing topic for research over the last decade as a key to understanding chirality generation. Accurate description and understanding of resona... Read More about Deciphering helix assembly in the heliconical nematic phase via tender resonant X-ray scattering.

The interplay between spatial and heliconical orientational order in twist-bend nematic materials (2021)
Journal Article
Saha, R., Feng, C., Welch, C., Mehl, G. H., Feng, J., Zhu, C., Gleeson, J. T., Sprunt, S., & Jakli, A. (2021). The interplay between spatial and heliconical orientational order in twist-bend nematic materials. Physical chemistry chemical physics : PCCP, 23(7), 4055-4063. https://doi.org/10.1039/d0cp06633h

The helical pitch formed by organic molecules, such as the α-helix of proteins, usually requires hydrogen bonding between chiral units and long-range positional order. It was recently found that certain liquid crystal oligomers can have a twist-bend... Read More about The interplay between spatial and heliconical orientational order in twist-bend nematic materials.

Molecular biaxiality determines the helical structure - infrared measurements of the molecular order in the nematic twist-bend phase of difluoro terphenyl dimer (2021)
Journal Article
Merkel, K., Loska, B., Welch, C., Mehl, G. H., & Kocot, A. (2021). Molecular biaxiality determines the helical structure - infrared measurements of the molecular order in the nematic twist-bend phase of difluoro terphenyl dimer. Physical chemistry chemical physics : PCCP, 23(7), 4151-4160. https://doi.org/10.1039/d1cp00187f

Fourier-transform infrared polarized spectroscopy was employed, to obtain the three components of the infrared absorbance for a series of bent-shaped dimers containing double fluorinated terphenyl core (DTC5Cn, n = 5, 7, 9, 11). The data were used to... Read More about Molecular biaxiality determines the helical structure - infrared measurements of the molecular order in the nematic twist-bend phase of difluoro terphenyl dimer.

The role of intermolecular interactions in stabilizing the structure of the nematic twist-bend phase (2021)
Journal Article
Merkel, K., Loska, B., Welch, C., Mehl, G. H., & Kocot, A. (2021). The role of intermolecular interactions in stabilizing the structure of the nematic twist-bend phase. RSC advances, 11(5), 2917-2925. https://doi.org/10.1039/d0ra10481g

The understanding of the relationship between molecular structure and the formation of the nematic twist-bend phase is still at an early stage of development. This is mainly related to molecular geometry, while the correlation between the nematic twi... Read More about The role of intermolecular interactions in stabilizing the structure of the nematic twist-bend phase.

Two helices from one chiral centre - self organization of disc shaped chiral nanoparticles (2020)
Journal Article
Mehl, G. H., Yu, H., Qu, W., & Liu, F. (2021). Two helices from one chiral centre - self organization of disc shaped chiral nanoparticles. Chemical science, 12(5), 1778-1782. https://doi.org/10.1039/d0sc05100d

Gold nanoparticles (AuNPs) have been prepared and surface-functionalized with a mixture of 1-hexanethiol co-ligands and chiral discogen ligands separated from a disulfide functionviaa flexible spacer. Polarized optical microscopy together with differ... Read More about Two helices from one chiral centre - self organization of disc shaped chiral nanoparticles.

Temperature dependence of bend elastic constant in oblique helicoidal cholesterics (2020)
Journal Article
Iadlovska, O. S., Babakhanova, G., Mehl, G. H., Welch, C., Cruickshank, E., Strachan, G. J., Storey, J. M. D., Imrie, C. T., Shiyanovskii, S. V., & Lavrentovich, O. D. (2020). Temperature dependence of bend elastic constant in oblique helicoidal cholesterics. Physical Review Research, 2(1), Article 013238. https://doi.org/10.1103/PhysRevResearch.2.013248

Elastic moduli of liquid crystals, known as Frank constants, are of quintessential importance for understanding fundamental properties of these materials and for the design of their applications. Although there are many methods to measure the Frank c... Read More about Temperature dependence of bend elastic constant in oblique helicoidal cholesterics.

A cholesteric liquid crystal device having stable uniform lying helix structure (2019)
Journal Article
Yip, W. C., Welch, C., Mehl, G. H., & Wilkinson, T. D. (2020). A cholesteric liquid crystal device having stable uniform lying helix structure. Journal of Molecular Liquids, 299, Article 112141. https://doi.org/10.1016/j.molliq.2019.112141

A cholesteric liquid crystal device having the uniform lying helix (ULH) structure shows stable and reversible characteristics and it has been demonstrated for the analogue modulation in 10 micro-second response time at room temperature. The device c... Read More about A cholesteric liquid crystal device having stable uniform lying helix structure.

Oligomeric odd-even effect in liquid crystals (2019)
Journal Article
Saha, R., Babakhanova, G., Parsouzi, Z., Rajabi, M., Gyawali, P., Welch, C., Mehl, G. H., Gleeson, J. T., Lavrentovich, O. D., Sprunt, S., & Jakli, A. (2019). Oligomeric odd-even effect in liquid crystals. Materials Horizons, 6(9), 1905-1912. https://doi.org/10.1039/c9mh00428a

Odd-even effects, oscillations in properties of materials comprised of an odd or even number of connected repeating units, are well-known phenomena in materials science. In organic materials, they are usually associated with the number of methylene... Read More about Oligomeric odd-even effect in liquid crystals.

The induction of the Ntb phase in mixtures (2018)
Journal Article
Ramou, E., Welch, C., Hussey, J., Ahmed, Z., Karahaliou, P. K., & Mehl, G. H. (2018). The induction of the Ntb phase in mixtures. Liquid crystals, 45(13-15), 1929-1935. https://doi.org/10.1080/02678292.2018.1524523

We report the induction of the Ntb phase over a wide temperature and concentration range in a binary system. This was achieved by addition of a flexible dopant without LC properties to a flexible dimer exhibiting only a nematic LC phase. The Ntb phas... Read More about The induction of the Ntb phase in mixtures.

Dynamic calorimetry and XRD studies of the nematic and twist-bend nematic phase transitions in a series of dimers with increasing spacer length (2018)
Journal Article
Stevenson, W. D., Zou, H. X., Zeng, X. B., Welch, C., Ungar, G., & Mehl, G. H. (2018). Dynamic calorimetry and XRD studies of the nematic and twist-bend nematic phase transitions in a series of dimers with increasing spacer length. Physical chemistry chemical physics : PCCP, 20(39), 25268-25274. https://doi.org/10.1039/c8cp05744c

A modulated and conventional DSC study of the transitions between the twist-bend nematic (Ntb), regular nematic (N) and isotropic liquid (Iso) phases was performed on a series of difluoroterphenyl-based dimers with (CH2)n spacers; n = 5, 7, 9, 11. Th... Read More about Dynamic calorimetry and XRD studies of the nematic and twist-bend nematic phase transitions in a series of dimers with increasing spacer length.

Flexoelectro-optic liquid crystal analog phase-only modulator with a 2π range and 1 kHz switching (2018)
Journal Article
Fells, J. A., Wang, X., Elston, S. J., Welch, C., Mehl, G. H., Booth, M. J., & Morris, S. M. (2018). Flexoelectro-optic liquid crystal analog phase-only modulator with a 2π range and 1 kHz switching. Optics letters, 43(18), 4362-4365. https://doi.org/10.1364/OL.43.004362

We present a flexoelectro-optic liquid crystal (LC) analog phase modulator with >2𝜋 phase range at a 1 kHz switching frequency. The chiral nematic LC mixture consists of the bimesogen CBC7CB with chiral dopant R5011, aligned in the uniform lying heli... Read More about Flexoelectro-optic liquid crystal analog phase-only modulator with a 2π range and 1 kHz switching.

Supramolecular organization of liquid-crystal dimers-bis-cyanobiphenyl alkanes on HOPG by scanning tunneling microscopy (2018)
Journal Article
Krzyzewska, K., Jaroch, T., Maranda-Niedbała, A., Pociecha, D., Górecka, E., Ahmed, Z., Welch, C., Mehl, G. H., Proń, A., & Nowakowski, R. (2018). Supramolecular organization of liquid-crystal dimers-bis-cyanobiphenyl alkanes on HOPG by scanning tunneling microscopy. Nanoscale, 10(34), 16201-16210. https://doi.org/10.1039/c8nr02069h

2D supramolecular organization of a series of six cyanobiphenyl bimesogens deposited on highly oriented pyrolytic graphite (HOPG) is studied by scanning tunneling microscopy (STM). The adsorbates
are 1,ω-bis(4-cyanobiphenyl-4’-yl)alkanes (CBnCB) with... Read More about Supramolecular organization of liquid-crystal dimers-bis-cyanobiphenyl alkanes on HOPG by scanning tunneling microscopy.

Tuning selective reflection of light by surface anchoring in cholesteric cells with oblique helicoidal structures (2018)
Journal Article
Iadlovska, O. S., Maxwell, G. R., Babakhanova, G., Mehl, G. H., Welch, C., Shiyanovskii, S. V., & Lavrentovich, O. D. (2018). Tuning selective reflection of light by surface anchoring in cholesteric cells with oblique helicoidal structures. Optics letters, 43(8), 1850-1853. https://doi.org/10.1364/ol.43.001850

Selective reflection of light by oblique helicoidal cholesteric (ChOH) can be tuned in a very broad spectral range by an applied electric field. In this work, we demonstrate that the peak wavelength of the selective reflection can be controlled by su... Read More about Tuning selective reflection of light by surface anchoring in cholesteric cells with oblique helicoidal structures.

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., Gleeson, J. T., Lavrentovich, O. D., Allender, D. W., Selinger, J. V., Jákli, A., & 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.