Controlling the Columnar Order in a Discotic Liquid Crystal by Kinetic Arrest of Disc Tumbling

Chen, Zhenxuan; Bishop, Camille; Thoms, Erik; Böck, Harald; Ediger, M. D.; Richert, Ranko; Yu, Lian

doi:10.1021/acs.chemmater.1c01331

Cited by 15 publications

(16 citation statements)

References 35 publications

(78 reference statements)

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“…The appearance of a glass transition indicates a certain disorder present in the material where this disorder in the ILC n is due to nanophase separation between the flexible alkyl side chains and the rigid aromatic cores. Such a nanophase separation has been previously reported for other materials such as homologous series of polymers bearing different alkyl chain length, , other discotic liquid crystals − and for recently investigated ILCs …”

Section: Resultssupporting

confidence: 63%

Side Chain Length-Dependent Dynamics and Conductivity in Self-Assembled Ion Channels

Kolmangadi

Smales

et al. 2022

J. Phys. Chem. C

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We study the molecular mobility and electrical conductivity of a homologous series of linear shaped columnar ionic liquid crystals ILCn, (n = 8, 10, 12, 14, 16) using broadband dielectric spectroscopy (BDS), specific heat spectroscopy (SHS), and X-ray scattering. We aim to understand how the alkyl chain length influences the dynamics and electric conductivity in this system. Two dielectrically active relaxation modes are observed, the γ and the α core process, that correspond to the localized fluctuations of the alkyl chains and cooperative motions of the aromatic core in the columns, respectively. Both the γ relaxation and the α core process slow down with increasing alkyl chain length. SHS reveals one relaxation process, the α alkyl process that has a similar temperature dependence as that of the α core process for ILC12, 14, and 16 but shifts to higher temperature for ILC8 and 10. For ILC12, 14, and 16, the absolute values of DC conductivity increase by 4 orders of magnitude at the transition from the plastic crystalline to hexagonal columnar phase. For ILC8 and 10, the DC conductivity behavior is similar to ionic liquids, where the conductivity is coupled with structural relaxation. Small-angle X-ray investigations reveal that both the intercolumnar distance and the disorder coherence length increase with alkyl chain length; conversely, the DC conductivity decreases monotonically.

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Section: Resultssupporting

confidence: 63%

Side Chain Length-Dependent Dynamics and Conductivity in Self-Assembled Ion Channels

Kolmangadi

Smales

et al. 2022

J. Phys. Chem. C

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“…The investigations about the molecular mobility of CLCs in the literature [17][18][19][20][21][22][23] reported multiple glassy dynamics probed in the plastic crystalline phase and/or in the columnar…”

Section: Introductionmentioning

confidence: 99%

“…These investigations revealed a localized molecular mobility and multiple glassy dynamics detected in the Cry phase, which was also reported by other groups. [17][18][19][20][21][22][23] For triphenylene-based DLCs, the detected glassy dynamics are attributed to cooperative fluctuations taking place in the columns and in the intercolumnar area. The faster glassy dynamics at lower temperatures (denoted as α2-relaxation [31][32][33] ) are assigned to rotational fluctuations of the disc-like core around the column axis coupled with parallel and perpendicular small scale motions of the triphenylene cores.…”

Section: Introductionmentioning

confidence: 99%

Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy and advanced calorimetry

Yildirim

Krause

Huber

et al. 2022

Journal of Molecular Liquids

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“…These considerations allow us to compare two types of LCs: thermotropic and lyotropic. In thermotropic LCs, the motions of rod-like and disk-like molecules in the uid state can be frozen into a solid state depending on how rapidly the temperature decreases 70 . These materials can vitrify via the kinetic arrest of molecular motions in the uid state, which dictates the degree of order in the resulting glassy state.…”

Section: Resultsmentioning

confidence: 99%

Kinetic arrest during the drying of cellulose nanocrystal films from aqueous suspensions analogous to the freezing of thermal motions

Chang

Oh‐e

2022

Preprint

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A comprehensive understanding of controlling the iridescence of cellulose films by manipulating the alignment and helical pitch of cellulose nanocrystals (CNCs) is required to advance cellulose photonics and its optoelectronic applications. Aqueous suspensions of CNCs exhibit a cholesteric liquid crystal (LC) phase with structural color; however, attaining a uniformly colored film is extremely difficult. Presumably, because multiple interrelated factors influence the CNC molecular alignment and helical pitch, existing models are not necessarily conclusive and remain a subject of debate. To eventually achieve homogeneously colored films, we compare aqueous CNC suspensions as a lyotropic liquid LC with thermotropic ones, and we spectroscopically confirm that the coloration of CNC droplets originates from the periodic CNC structure. The suspension drying process significantly influences the quality of iridescence of CNC films. Rapidly drying a droplet of a CNC suspension forms a concentric rainbow film, with red edges and a blue center, typical of the coffee-ring effect observed in air-dried films. By contrast, slow drying under controlled humidity, which reduces capillary flow, provides higher uniformity and a large blue area. Orbitally shaking films while drying under high humidity further improves the uniformity. Therefore, the evaporation rate significantly influences the thermodynamically stabilized helical pitch of CNCs, which determines the structural color. We qualitatively model the kinetic arrest induced by the rapid evaporation of lyotropic LCs in a manner equivalent to that induced by the rate of temperature change in thermotropic LCs and other materials.

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Controlling the Columnar Order in a Discotic Liquid Crystal by Kinetic Arrest of Disc Tumbling

Cited by 15 publications

References 35 publications

Side Chain Length-Dependent Dynamics and Conductivity in Self-Assembled Ion Channels

Side Chain Length-Dependent Dynamics and Conductivity in Self-Assembled Ion Channels

Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy and advanced calorimetry

Kinetic arrest during the drying of cellulose nanocrystal films from aqueous suspensions analogous to the freezing of thermal motions

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