Deuterium NMR Study of Slow Relaxation Dynamics in a Polymer-like Micelles System after Flow-Induced Orientation

Angelico, Ruggero; Burgemeister, Daniel; Ceglie, Andrea; Olsson, Ulf; Palazzo, Gerardo; Schmidt, Claudia

doi:10.1021/jp0356259

Cited by 14 publications

(16 citation statements)

References 17 publications

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“…In all cases, materials in a disordered state at rest will shift to an orientational ordered state with applied shear, which corresponds to a shift from high viscosity to low viscosity. This means shear-thinning behavior is an entropy-decreasing process [30,31]. Bitumen is commonly recognized as a multi-disperse colloidal system, where high molecular weight asphaltene micelles are peptized by resins in low molecular weight maltenes.…”

Section: Shear-thinning Behaviorsmentioning

confidence: 99%

Non-Newtonian Behaviors of Crumb Rubber-Modified Bituminous Binders

et al. 2018

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Crumb rubber-modified bitumen (CRMB) has been utilized in the asphalt paving industry for decades due to its various benefits. The complex interaction between bitumen and crumb rubber as well as the addition of warm-mix additives makes the typical laws of Newtonian fluids insufficient to describe the behaviors of highly modified bituminous binders. To systematically explore the non-Newtonian behaviors of CRMB, a dynamic shear rheometer was utilized to apply shear loading on the samples at various temperatures and shear rates. Results show that the viscosity of different binders are highly temperature- and shear rate-dependent, while highly modified binders exhibit more obvious shear-thinning behaviors at certain temperatures. With the help of zero shear viscosity and yield stress, the shear-thinning behaviors of non-Newtonian binders can be sufficiently characterized. The Arrhenius equation is invalid to describe viscosity-temperature characteristics of bitumen in the non-Newtonian region. A second-order polynomial function was proposed to characterize the viscosity-temperature dependence with a high correlation degree.

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Section: Shear-thinning Behaviorsmentioning

confidence: 99%

Non-Newtonian Behaviors of Crumb Rubber-Modified Bituminous Binders

et al. 2018

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“…Time-resolved deuterium NMR study on wormlike micelles under shear has been reported. 81 A micellar system made of soybean phosphatidylcholine, D 2 O, and cyclohexane has been studied in the vicinity of the isotropic/nematic transition but positioned in the equilibrium isotropic phase. The D 2 O dispersed in the micellar core was used as a probe to study the relaxation of a shear-induced nematic phase back to the isotropic liquid state, after cessation of shear.…”

Section: Chiral Smectic Lyotropic and Polymeric Systemsmentioning

confidence: 99%

Oriented molecules

Khetrapal¹,

Ramanathan²

1998

Nuclear Magnetic Resonance

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“…1 are the experimental data of the time dependence of quadrupole splitting of the NMR 2 H spectrum from lecithin/D 2 O/cyclohexane taken from [6]. A solid line in this figure shows the theoretical dependence approximated the experimental curve by Eq.…”

mentioning

confidence: 96%

“…shows the experimentally obtained time dependence of the ordering parameter for lecithin/D 2 O/cyclohexane measured by the neuron scattering technique in[6]. A solid line shows the theoretical curve, Eq.…”

mentioning

confidence: 96%

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Determination of rheological parameters of liquid crystals with zero anisotropy of diamagnetic susceptibility

Korotey

Sinyavskii

2007

Russ Phys J

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A new method for determination of rheological parameters of liquid crystals with zero anisotropy of diamagnetic susceptibility is proposed, which is based on the measurement of the quadrupole splitting line of the NMR 2 H spectrum. The method provides higher information content of the experiments, with the shear flow discarded from consideration, compared to that obtained by the classical Leslie-Ericksen theory. A comparison with the experiment is performed, the coefficients of anisotropic viscosity of lecithin/D 2 O/cyclohexane are determined, and a conclusion is drawn as concerns the domain shapes.The liquid-crystal state of matter is appealing to investigators for two reasons: due to high optical sensitivity of liquid crystals to electric field variation under negligibly low voltage and low consumed power, and due to a striking variety of physical effects in liquid crystals, being a consequence of their structural arrangement. It is their viscosity that controls running speed of LC devices. It is therefore very critical to determine the value of viscosity factors of liquid crystals.Currently, there is a great variety of techniques that allow determining rheological parameters of anisotropic liquids. For instance, using rotary or capillary viscometers one can measure the dynamic and kinematic viscosity, the method of ultrasonic shear provides for determination of the value of dynamic viscosity, the examination of the Poiseuille or Couette flow makes it possible to find the Mesovich viscosity coefficients, etc.A tendency to form liquid-crystal phases is inherent in those substances whose molecules have shape anisotropy, similarly to rods or discs. A distinguishing feature of liquid-crystal states is a tendency of molecular axes to arrange along the common axis referred to as director. Being in a constant magnetic field, the director is adjusted primarily along the filed lines. For specimens with zero anisotropy of diamagnetic susceptibility, adjustment of the director could be achieved by superposition of shear flow. Upon disruption of the shear flow, the specimen's domain gets to be misoriented, the mean ordering parameter is decreased and so is the mean quadrupole splitting of lines of the NMR spectrum. Using experiments, one can determine the dependence of the ordering parameter value and that of the mean splitting of the NMR spectrum of the specimen on time.We constructed our models according to the classical Leslie-Ericksen-Parody theory [1,2]. Its disadvantage is that it appears impossible to determine rheological parameters of liquid crystals for this type of experiment. The purpose of our work was to modify the classical equations in order to increase the information content of the experimental data and to provide an adequate description of anisotropic liquids. The system of equations describing the dynamics of the director in space can be written as [3]

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Deuterium NMR Study of Slow Relaxation Dynamics in a Polymer-like Micelles System after Flow-Induced Orientation

Cited by 14 publications

References 17 publications

Non-Newtonian Behaviors of Crumb Rubber-Modified Bituminous Binders

Non-Newtonian Behaviors of Crumb Rubber-Modified Bituminous Binders

Oriented molecules

Determination of rheological parameters of liquid crystals with zero anisotropy of diamagnetic susceptibility

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