Hydrodynamic effects on chiral induction

Crusats, Joaquim; El‐Hachemi, Zoubir; Ribó, Josep M.

doi:10.1039/b916369g

Cited by 96 publications

(90 citation statements)

References 50 publications

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“…[440][441][442] However, there is some evidence to suggest that stirring can itself template the assembly of helical fibres, producing a bias in handedness dependent on the sense of rotation of the liquid medium. 443,444 For example, Escudero et al showed that J-aggregated bilayers of a sulfonated porphyrin can undergo folding above a critical width, producing different CD signals depending on the stirring direction. 445 Ultrasound, meanwhile, was utilised by Azeroual et al to disrupt helical stacks of an achiral foldamer, allowing it to reassemble into homochiral fibres in the presence of the chiral template diethyl tartrate.…”

Section: Gels Under Stressmentioning

confidence: 99%

Gels with sense: supramolecular materials that respond to heat, light and sound

2016

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. (2016) 'Gels with sense : supramolecular materials that respond to heat, light and sound.', Chemical society reviews., 45 (23). pp. 6546-6596. Further information on publisher's website:https://doi.org/10.1039/C6CS00435KPublisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Advances in the field of supramolecular chemistry have made it possible, in many situations, to reliably engineer soft materials to address a specific technological problem. Particularly exciting are "smart" gels that undergo reversible physical changes on exposure to remote, non-invasive environmental stimuli. This review explores the development of gels which are transformed by heat, light and ultrasound, as well as other mechanical inputs, applied voltages and magnetic fields. Focusing on small-molecule gelators, but with reference to organic polymers and metal-organic systems, we examine how the structures of gelator assemblies influence the physical and chemical mechanisms leading to thermo-, photo-and mechano-switchable behaviour. In addition, we evaluate how the unique and versatile properties of smart materials may be exploited in a wide range of applications, including catalysis, crystal growth, ion sensing, drug delivery, data storage and biomaterial replacement.

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Section: Gels Under Stressmentioning

confidence: 99%

Gels with sense: supramolecular materials that respond to heat, light and sound

2016

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“…[3,4] In some specific cases, a system wholly composed of achiral building blocks can also be organized to form chiral species under certain conditions. [5][6][7][8][9][10] This latter scenario is a particularly significant subject because of its intimate relation to the mirror symmetry breaking of a system, which can provide fertile opportunities for the understanding of supramolecular chirogenic processes, and even for the origin of chirality in nature. An interesting phenomenon that always occurs in such systems is that the chirality generally manifests itself in a stochastic manner.…”

Section: Introductionmentioning

confidence: 99%

“…An interesting phenomenon that always occurs in such systems is that the chirality generally manifests itself in a stochastic manner. For the control of the macroscopic chirality of these kinds of systems, several significant strategies have been proposed, [6][7][8][9][10] of which mechanically induced preferred chirality has attracted much attention. [6][7][8][9] For example, it has been reported that achiral species can be organized to form chiral assemblies, the chirality of which can be selected by clockwise (CW) or counterclockwise (CCW) stirring.…”

Section: Introductionmentioning

confidence: 99%

Left or Right? The Direction of Compression‐Generated Vortex‐Like Flow Selects the Macroscopic Chirality of Interfacial Molecular Assemblies

Chen

et al. 2011

Chemistry A European J

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A new method is described through which the macroscopic chirality of interfacial molecular assemblies of an achiral porphyrin can be mechanically controlled using an original yet efficient Langmuir-Blodgett (LB) technique. By using the unilateral compression geometry, we find that the assemblies deposited from the mirror regions of the LB trough display mirror macroscopic chirality. It is indicated that vortex-like flows could be generated during compression, and that it is the direction of this compression-generated vortex-like flow that determine the macroscopic chirality of the formed assemblies. Moreover, the standard sample-fabrication method with bilateral compression geometry is reformed, and we find that the samples formulated around the left-hand- and right-hand-side Langmuir barriers display opposite macroscopic chiralities. The results suggest that mechanically controlled supramolecular chirogenesis could be efficiently realized through such an LB technique. The investigation establishes a new forum for further investigation of the mechanically induced preferred supramolecular chirality in terms of interfacial organization, and provides the old LB technique with new opportunities for controlling the macroscopic chirality of a supramolecular system that is wholly composed of achiral units.

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“…Although several experimental studies report chirality-specific flow effects-on scales from molecular (porphyrin aggregation during rotary evaporation) 14,15 , through microscopic (helical bacteria 4 and particles 16 ), to macroscopic 13,17,18 -they remain largely phenomenological. Part of the problem is the possibly ambiguous interpretation of data [19][20][21] (for example, from circular dichroism) and the experimental design in which vortex flows are implemented with imprecise systems such as rotary evaporators or magnetic stirrers 22 , for which the flow structure on different length scales is largely unknown.…”

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confidence: 99%

Vortex flows impart chirality-specific lift forces

et al. 2015

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Recent reports that macroscopic vortex flows can discriminate between chiral molecules or their assemblies sparked considerable scientific interest both for their implications to separations technologies and for their relevance to the origins of biological homochirality. However, these earlier results are inconclusive due to questions arising from instrumental artifacts and/or insufficient experimental control. After a decade of controversy, the question remains unresolved-how do vortex flows interact with different stereoisomers? Here, we implement a model experimental system to show that chiral objects in a Taylor-Couette cell experience a chirality-specific lift force. This force is directed parallel to the shear plane in contrast to previous studies in which helices, bacteria and chiral cubes experience chiralityspecific forces perpendicular to the shear plane. We present a quantitative hydrodynamic model that explains how chirality-specific motions arise in non-linear shear flows through the interplay between the shear-induced rotation of the particle and its orbital translation. The scaling laws derived here suggest that rotating flows can be used to achieve chiral separation at the micro-and nanoscales.

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Hydrodynamic effects on chiral induction

Cited by 96 publications

References 50 publications

Gels with sense: supramolecular materials that respond to heat, light and sound

Gels with sense: supramolecular materials that respond to heat, light and sound

Left or Right? The Direction of Compression‐Generated Vortex‐Like Flow Selects the Macroscopic Chirality of Interfacial Molecular Assemblies

Vortex flows impart chirality-specific lift forces

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