Liquid‐crystalline ordering in solutions of polyelectrolytes

Nyrkova, I. A.; Shusharina, Nadya; Khokhlov, Alexei R.

doi:10.1002/mats.1997.040060602

Cited by 24 publications

(19 citation statements)

References 34 publications

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“…Most predictions of Refs. [24,25], including the existence of the nematic-nematic coexistence were confirmed in Ref. [26], using a Debye-Hückel-like theory that includes some many-rod correlations.…”

Section: Introductionmentioning

confidence: 78%

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Phase diagrams of charged colloidal rods: Can a uniaxial charge distribution break chiral symmetry?

Drwenski

Dussi

Hermes

et al. 2016

The Journal of Chemical Physics

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We construct phase diagrams for charged rodlike colloids within the second-virial approximation as a function of rod concentration, salt concentration, and colloidal charge. Besides the expected isotropic-nematic transition, we also find parameter regimes with a coexistence between a nematic and a second, more highly aligned nematic phase including an isotropic-nematic-nematic triple point and a nematic-nematic critical point, which can all be explained in terms of the twisting effect. We compute the Frank elastic constants to see if the twist elastic constant can become negative, which would indicate the possibility of a cholesteric phase spontaneously forming. Although the twisting effect reduces the twist elastic constant, we find that it always remains positive. In addition, we find that for finite aspect-ratio rods the twist elastic constant is also always positive, such that there is no evidence of chiral symmetry breaking due to a uniaxial charge distribution.

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Section: Introductionmentioning

confidence: 78%

“…In Refs. [24,25], a scaling theory was used to give qualitative predictions for charged rods. Interestingly, in a certain region of low charge density and moderate screening they predict that a competition between steric and electrostatic effects leads to a coexistence between a nematic and a highly oriented nematic phase.…”

Section: Introductionmentioning

confidence: 99%

Phase diagrams of charged colloidal rods: Can a uniaxial charge distribution break chiral symmetry?

Drwenski

Dussi

Hermes

et al. 2016

The Journal of Chemical Physics

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“…Clear birefringent phases are present in the Zn 2+ and Ca 2+ salts, but there is less evidence of a birefringence phase both in the K + salt and in the acid form 66, 67. Thus, the recent developments of ionic polymers (also known as polyelectrolytes) that exhibit a lyotropic LC phase in various organic solvents suggest that both an extension of the theories of polyelectrolytes,68–71 which are poorly understood, and a suitable experimental technique to determine their persistence lengths could be worthwhile.…”

Section: Resultsmentioning

confidence: 99%

Intravascular ultrasound and quantitative coronary angiography assessment of late in‐stent restenosis: In vivo human correlation and methodological implications

Prati¹,

Pawłowski

Sommariva³

et al. 2002

Cathet Cardio Intervent

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Quantitative coronary angiography (QCA) is routinely used for assessment of strategies aimed at reducing in-stent restenosis. Yet QCA enables only the measurement of luminal variation of stented segments and, unlike intravascular ultrasound (IVUS), provides only an indirect estimation of late in-stent neointimal formation, which has a key role in the process of in-stent restenosis. The aims of the present study were to correlate the IVUS measurement of in-stent intimal hyperplasia (IH) with QCA indexes of restenosis, to find out whether QCA is an adequate surrogate of IVUS, and, using either QCA and IVUS data, to define the sample sizes needed to demonstrate the effectiveness of strategies to reduce in-stent restenosis. The database of the European Imaging Laboratory was used to screen 154 stents implanted between 1997 and 2001 and studied by IVUS at 6 +/- 1 months of follow-up. All cases underwent serial QCA assessment (preintervention, postintervention, and follow-up). Only 131 cases with single stent implantation in native coronary arteries were included in the study. Stent restenosis, defined as percent diameter stenosis (DS) > 50%, was present at QCA in 69 out of 131 cases (53%). Linear regression analyses were performed to correlate the amount of IH, calculated by IVUS as the average of all cross-section areas (CSA; mean % IH CSA) and QCA indexes of restenosis (late loss and % DS). A positive significant correlation was found between IVUS mean % IH CSA and QCA % DS (r = 0.74; P < 0.0001) and between IVUS mean % IH CSA and QCA late loss (r = 0.72; P < 0.0001). Based on IVUS measurements of mean % IH CSA, a total sample size of 74 stents would be required in a two-arm comparison to have 0.80 power to detect at 0.05 significant level a 30% difference between two compared groups. Alternatively, adopting the QCA late loss, 230 stents would be required. QCA measurements of late in-stent restenosis are well correlated with IVUS calculation of in-stent neointimal formation. IVUS assessment of IH allows smaller sample sizes than QCA to document significant reductions of in-stent restenosis. Therefore, the use of IVUS should be encouraged in comparison studies aimed at revealing significant neointimal differences in small sample size populations.

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“…In Refs. [35,36] rod lengths of the order of (or larger than) the Debye length are considered, at the expense, however, of ignoring many of the prefactors such that the theory is essentially a scaling theory. Interestingly, this scaling theory predicts nematic-nematic coexistence in some parameter regime, which was later confirmed in Ref.…”

Section: Introductionmentioning

confidence: 99%

Effective shape and phase behavior of short charged rods

2009

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We explicitly calculate the orientation-dependent second virial coefficient of short charged rods in an electrolytic solvent, assuming the rod-rod interactions to be a pairwise sum of hard-core and segmental screened-Coulomb repulsions. From the parallel and isotropically averaged second virial coefficient, we calculate the effective length and diameter of the rods, for charges and screening lengths that vary over several orders of magnitude. Using these effective dimensions, we determine the phase diagram, where we distinguish a low-charge and strong-screening regime with a liquid crystalline nematic and smectic phase, and a high-charge and weak-screening regime with a plastic crystal phase in the phase diagram.

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Liquid‐crystalline ordering in solutions of polyelectrolytes

Cited by 24 publications

References 34 publications

Phase diagrams of charged colloidal rods: Can a uniaxial charge distribution break chiral symmetry?

Phase diagrams of charged colloidal rods: Can a uniaxial charge distribution break chiral symmetry?

Intravascular ultrasound and quantitative coronary angiography assessment of late in‐stent restenosis: In vivo human correlation and methodological implications

Effective shape and phase behavior of short charged rods

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