Filaments formed in the hexagonal columnar liquid crystal phase of star-shaped oligobenzoates

Ostapenko, Tanya; Weyland, Marvin; Eremin, Alexey; Lehmann, Matthias; Stannarius, Ralf

doi:10.1080/02678292.2012.747736

Cited by 7 publications

(3 citation statements)

References 32 publications

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“…Such a paradoxical situation seems not to be exceptional. [7,26] Intermediate between the disordered columnar phase, which is made of long and resistant columns, and the quasinematic case, in which the columns are short and fragile, we may naturally observe a continuous range of cases that exhibit quasi-viscous behaviors for stresses above the low plasticity threshold, which is necessary for breaking the entangled columns. Their effective viscosities will not only depend on the shear viscosity of a perfectly oriented strand, but also on the length of the columns, their degree of entanglement, the contact areas along the fractures between sliding domains, and so on.…”

Section: Sliding Mechanismmentioning

confidence: 99%

“…Such a nematic-like behavior in a strand of disordered columnar strands is consistent with the mechanical observations reported by N. Clark et al in HAT11, [7] and with the measurements realized by R. Stannarius et al in a different compound, whereby, in the absence of any applied stress, they evidenced a decrease in the strand diameter over several hours. [26]…”

Section: Nematic-like Behaviormentioning

confidence: 99%

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Elongation of Discotic Liquid Crystal Strands and Lubricant Effects

Bhattacharyya

Galerne

2013

ChemPhysChem

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After a short review on the physics of pulled threads and their mechanical properties, the paper reports and discusses the strand elongation of disordered columnar phases, hexagonal or lamella-columnar, of small molecules or polymers. The mechanical properties appear to be relevant to the length of the columns of molecules compared to the thread length, instead of the usual correlation length. If, taking the entanglement effect into account, the column length is short, the strand exhibits rather fluid-like properties that may even look nematic-like at the macroscopic scale. The Plateau-Rayleigh instability breaks the thread shortly thereafter. However, because the hydrodynamic objects are the columns instead of the molecules, the viscosity is anomalously large. The observations show that the strands in the columnar phases are made of filaments, or fibrils, which are bundles of columns of molecules. This explains the grooves and rings, which are observed on the antenna or bamboo-like strand profiles. On pulling a strand, the elongation stress eventually exceeds the plasticity threshold, thus breaking the columns and the filaments. As a result, cracks, more exactly, giant dislocations are formed. These change the strand thickness by steps of different birefringence colors. Interestingly, the addition of a solute may drastically change the effective viscosity of the columnar phase and its mechanical properties. Some solutes, such as alkanes, exhibit lubricant and detangling properties, whereas others such as triphenylene, are antilubricant.

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Section: Sliding Mechanismmentioning

confidence: 99%

Section: Nematic-like Behaviormentioning

confidence: 99%

Elongation of Discotic Liquid Crystal Strands and Lubricant Effects

Bhattacharyya

Galerne

2013

ChemPhysChem

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“…The emulsion layer of the settling tank after breaking the emulsion is excessively thick, and the water content in the overflow port is likewise high, affecting the gathering system's regular operation. Because crude oil emulsions are derived from various production blocks, the mechanism of emulsification and stabilization of extracted crude oil, the relationship between different emulsions and the effect of emulsion breaking, and the mechanism of action of low-temperature emulsion breakers are all insufficiently defined [17,18]. Common low-temperature demulsifiers include ester copolymers [19], derivatives of highly polar organic ammonia [20], hydrophobically linked trimers [21], silicone-containing demulsifiers [22], polyethylene polyamine block polyethers [23], and phenol-amino aldehyde resin polyether demulsifiers [24].…”

Section: Introductionmentioning

confidence: 99%

Efficient Demulsification Performance of Emulsified Condensate Oil by Hyperbranched Low-Temperature Demulsifiers

Jiang,

Li,

et al. 2023

Molecules

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Focusing on the problem of poor demulsification performance of light crude oil emulsions in low-permeability oilfields at low temperatures, the composition of the emulsion samples, clay particle size distribution, and the viscosity–temperature relationship curve of samples were analyzed. Based on the results of emulsion composition analysis and characteristics, the bottle test method was used to analyze the demulsifying effect of different commercial types of demulsifiers, revealing the demulsification mechanism. The field tests confirm the demulsification capabilities of Polyoxyethylene polyoxypropylene quaternized polyoxyolefins surfactants (PR demulsifiers). The results reveal that PR demulsifiers combine the features of decreasing the interfacial tension between oil and water and adsorbing SiO2, allowing for quick demulsification and flocculation at low temperatures. This research serves as a theoretical and practical foundation for the study and advancement of low-temperature demulsification technology in oilfields.

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Star‐Shaped Mesogens

Lehmann

2014

Handbook of Liquid Crystals

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Star‐shaped molecules are exciting non‐conventional mesogens in which more than two linear arms are symmertrically attached to a core building block via covalent or supramolecular bonds. The molecular structures comprise flexible, semi‐flexible and shape‐persistent scaffolds which may realize all kinds of mesophase topologies by nanosegregation. This requires different modes of self‐assembly depending on the mesogen structure, flexibility and void between the arms. Functionality can be incorporated by cores, arms and guest molecules generating multifunctional, highly organized complex materials for applications.

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Filaments formed in the hexagonal columnar liquid crystal phase of star-shaped oligobenzoates

Cited by 7 publications

References 32 publications

Elongation of Discotic Liquid Crystal Strands and Lubricant Effects

Elongation of Discotic Liquid Crystal Strands and Lubricant Effects

Efficient Demulsification Performance of Emulsified Condensate Oil by Hyperbranched Low-Temperature Demulsifiers

Star‐Shaped Mesogens

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