Macroscopic Helical and Cylindrical Morphologies from Achiral 1,3-Diynes

Lindsell, W. Edward; Preston, Peter N.; Seddon, John M.; Rosair, Georgina M.; Woodman, Thomas A. J.

doi:10.1021/cm000172v

Cited by 33 publications

(28 citation statements)

References 32 publications

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“…Some indications of this effect have been seen experimentally. 48,49 A specific model for chiral symmetry-breaking leading to tubule formation was proposed by Seifert et al 50 They point out that each monolayer of a bilayer membrane is characterized by its own direction of molecular tilt, m + and m -. These monolayer tilt directions are usually aligned with each other, but under some circumstances the molecules might pack with a relative angle of R between m + and m -.…”

Section: Models Based On Chiral Elastic Propertiesmentioning

confidence: 99%

Theory of Self-Assembled Tubules and Helical Ribbons

2001

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Many types of amphiphilic molecules self-assemble in solution to form cylindrical tubules and helical ribbons.Some examples include diacetylenic lipids, amide amphiphiles, bile, and diblock copolymers. Researchers have proposed a variety of models to explain the formation of these high-curvature structures. These models can be divided into two broad categories: models based on the chiral elastic properties of membranes, and models based on other effects, including electrostatic interactions, elasticity of orientational order, and spontaneous curvature. In this paper, we review the range of theoretical approaches and compare them with relevant experiments. We argue that the category of models based on chiral elastic properties provides the most likely explanation of current experimental results, and we propose further theoretical and experimental research to give a more detailed test of these models.

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Section: Models Based On Chiral Elastic Propertiesmentioning

confidence: 99%

Theory of Self-Assembled Tubules and Helical Ribbons

2001

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“…It was clear from the outset of our work here that a number of Bernauer's mesoscale helices were chimera. But, observations of bona fide crystalline helices [13][14][15][16][17][18][19][20][21][22][23][24] prodded our search for the subset of the banded spherulites in GK that were indeed helical.…”

Section: Introductionmentioning

confidence: 99%

Bernauer′s Bands

et al. 2011

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Ferdinand Bernauer proposed in his monograph, "Gedrillte" Kristalle (1929), that a great number of simple, crystalline substances grow from solution or from the melt as polycrystalline spherulites with helically twisting radii that give rise to distinct bull's-eye patterns of concentric optical bands between crossed polarizers. The idea that many common molecular crystals can be induced to grow as mesoscale helices is a remarkable proposition poorly grounded in theories of polycrystalline pattern formation. Recent reinvestigation of one of the systems Bernauer described revealed that rhythmic precipitation in the absence of helical twisting accounted for modulated optical properties [Gunn, E. et al. J. Am. Chem. Soc. 2006, 128, 14234-14235]. Herein, the Bernauer hypothesis is re-examined in detail for three substances described in "Gedrillte" Kristalle, potassium dichromate, hippuric acid, and tetraphenyl lead, using contemporary methods of analysis not available to Bernauer, including micro-focus X-ray diffraction, electron microscopy, and Mueller matrix imaging polarimetry. Potassium dichromate is shown to fall in the class of rhythmic precipitates of undistorted crystallites, while hippuric acid spherulites are well described as helical fibrils. Tetraphenyl lead spherulites grow by twisting and rhythmic precipitation. The behavior of tetraphenyl lead is likely typical of many substances in "Gedrillte" Kristalle. Rhythmic precipitation and helical twisting often coexist, complicating optical analyses and presenting Bernauer with difficulties in the characterization and classification of the objects of his interest.

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“…Cholsäurehelices zeigen in Rçntgenpulverstreuexpe-rimenten einen hohen Kristallinitätsgrad, was Vergleiche mit verwundenen Kristallen nahelegt, [44] morphologisch stellen sie aber Aggregate dar. 10,12-Tricosadynoesäureanhydrid bildet helikal verwundene Bänder, [45] die als helikale Aggregate amphiphiler Moleküle angesehen werden; [37] optische Mikroskopie weist auf ein einzelnes verwundenes kristallines Band hin. Verwindung von Cholesterin-Flüssigkristallen wird hier nicht diskutiert, da infinitesimale Verwindungen zwischen Molekülschichten nicht mit einer typischen kristallographischen Raumgruppe vereinbar sind.…”

Section: Wwwangewandtedeunclassified

“…[185][186][187][188][189][190][191][192][193][194][195][196][197] Mesoskopische verwundene Kristalle (ca. 500 nm < h < 100 mm) umfassen 10,12-Tricosadynoesäureanhydrid [45] und [198] Der chirale polycyclische aromatische Kohlenwasserstoff Decacyclen bildet links-und rechtshändig verwundene mesoskalige Bänder, [199] und 2,5-Di-tert-butyl-1,4-dimethoxybenzol-Platten biegen sich bei der Präzipitation aus Lçsung. [200] Mannit, [105] Hippursäure [7,8] und Resorcin [201] kçnnen in diesem Grçßenbereich als einzelne verwundene Nadeln und auch als gebänderte Sphärolithe gezüchtet werden.…”

Section: Geschichteunclassified

Wachstumsinduziertes Biegen und Verwinden von Einkristallen

et al. 2014

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Kristalle von verschiedenen Stoffen, z. B. von Elementen, Mineralien, einfachen Salzen, organischen Molekülkristallen und hochmolekularen Polymeren, können die Translationsfernordnung aufgeben, indem sie sich während des Wachstums verwinden und verbiegen. Diese Erscheinungen wurden bei Kristallen im Größenbereich von Nano‐ bis Zentimetern beobachtet. Wir analysieren, wie und warum viele Materialien solche oft drastischen nichtkristallographischen Verzerrungen wählen und betonen dabei die Kristallchemie, die zu Spannungen an Oberflächen von Kristalliten oder innerhalb des Volumens führt.

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Macroscopic Helical and Cylindrical Morphologies from Achiral 1,3-Diynes

Cited by 33 publications

References 32 publications

Theory of Self-Assembled Tubules and Helical Ribbons

Theory of Self-Assembled Tubules and Helical Ribbons

Bernauer′s Bands

Wachstumsinduziertes Biegen und Verwinden von Einkristallen

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