Probing the pore structure of a chiral periodic mesoporous organosilica using liquid crystals

Vallamkondu, Jayalakshmi; Wood, Thomas K.; Basu, Rajratan; Du, Jenny; Blackburn, Thomas; Rosenblatt, Charles; Crudden, Cathleen M.; Lemieux, Robert P.

doi:10.1039/c2jm33089j

Cited by 15 publications

(9 citation statements)

References 61 publications

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“…29 This is a common technique to measure h vs. E (f) for the electroclinic effect in chiral LCs. 28,[30][31][32][33] In mean field theory, the field-induced tilt angle h ¼ kE ðTÀT AC Ã Þ , 23 where T AC* is the smectic-A to smectic-C* transition temperature and k is a proportionality constant, which reflects the chiral coupling to the electric field, and vanishes in the absence of chirality. Figure 2 shows the tilt angle h as a function of the rms applied field E at f ¼ 1 kHz for (a) pure 9OO4 and for (b) the 9OO4 þ GP mixture.…”

Section: Experiments Results and Discussionmentioning

confidence: 99%

Detection of graphene chirality using achiral liquid crystalline platforms

Basu

Kinnamon

Garvey

2015

Journal of Applied Physics

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Monolayer graphene flakes were dispersed at low concentrations into two achiral liquid crystals (LCs) alkoxyphenylbenzoate (9OO4) and 4-cyano-4 0 -pentylbiphenyl (5CB), separately. The presence of graphene resulted in two types of chiral signatures in the LCs: an electroclinic effect (a polar tilt of the LC director perpendicular to, and linear in, an applied electric field) in the smectic-A phase of 9OO4, and a macroscopic helical twist of the LC director in the nematic phase of 5CB. Graphene flakes generally possess strain chirality and edge chirality. The non-covalent interactions between the LC molecules and chiral graphene flakes induce molecular conformational deracemization in the LC, exhibiting a bulk electroclinic effect and a macroscopic helical twist.

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Section: Experiments Results and Discussionmentioning

confidence: 99%

Detection of graphene chirality using achiral liquid crystalline platforms

Basu

Kinnamon

Garvey

2015

Journal of Applied Physics

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“…27 To the contrary, chirality induction in mesoporous organosilica showed that incorporated binaphthyl derivatives are very effective dopants in transferring chirality to the solid state due to the point of attachment and orientation of the chiral axis. 28,29 Considering these facts, we report the successful control of the handedness of HNF mod s using axially chiral additives featuring a commensurate bent-shape when the mixture is confined in nanopores. The homochirality of the resulting nanofilaments is observed by scanning electron microscopy (SEM) and confirmed by circular dichroism (CD) spectropolarimetry.…”

Section: Introductionmentioning

confidence: 94%

Directing the Handedness of Helical Nanofilaments Confined in Nanochannels Using Axially Chiral Binaphthyl Dopants

Shadpour

Nemati

Liu

et al. 2020

ACS Appl. Mater. Interfaces

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In this work, we demonstrate control of the handedness of semicrystalline modulated helical nanofilaments (HNF mod s) formed by achiral bent-core liquid crystal molecules by axially chiral binaphthyl-based additives as guest molecules solely under spatial nanoconfinement in anodic aluminum oxide nanochannels. The molecules of the same chiral additives are expelled from the HNF mod s in the bulk, and as a result thereof do not affect the handedness or helical pitch of bulk HNF mod s, resulting in an HNF mod conglomerate with chiralitypreserving growth within each domain. However, under confinement these axially chiral guest molecules, likely embedded in the HNF mod host, do affect the helicity of the HNF mod s. The configuration of the axially chiral molecules decides the HNF mod helix handedness and their concentration, and the helix angle is related to the helical pitch of the HNF mod s. In addition to local imaging data obtained by scanning electron microscopy, global studies by thin-film circular dichroism spectropolarimetry support the imaging results.

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“…The inclusion of bis-siloxanes derived from such biaryls into silica materials permits incorporation of chirality into the material. Furthermore, the presence of resolved chiral biaryl species such as 2 – 9 in a bulk PMO comprised of fluxionally chiral monomers such as 1 provides an intriguing possibility to transfer of chirality in the solid state from dopant to “host”. ,, We first reported this concept in 2008 using the resolvable diester 2 as a chiral dopant and monomer 1 as host …”

Section: Introductionmentioning

confidence: 99%

Chiral Periodic Mesoporous Organosilicas: Probing Chiral Induction in the Solid State

MacLean

Wood

et al. 2014

Chem. Mater.

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The production of a variety of PMO materials made with 1,1′-biphenylene monomers, and the inclusion of 1,1′-binaphthalene dopants is described. The effect of the point of attachment with regard to the biaryl axis was studied, and it was found that the highest level of chirality transfer is obtained when the biaryl axis is not restricted by the polymerization point. In addition, the actual loading of dopant was found to vary considerably depending on the synthesis procedure, and the effect of dopant, even at low level, was magnified under basic conditions when more ordered materials are produced.

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Probing the pore structure of a chiral periodic mesoporous organosilica using liquid crystals

Cited by 15 publications

References 61 publications

Detection of graphene chirality using achiral liquid crystalline platforms

Detection of graphene chirality using achiral liquid crystalline platforms

Directing the Handedness of Helical Nanofilaments Confined in Nanochannels Using Axially Chiral Binaphthyl Dopants

Chiral Periodic Mesoporous Organosilicas: Probing Chiral Induction in the Solid State

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