Anomalous behavior of micellar solutions in electric birefringence measurements

Hoffmann, Hartmut; Kraemer, U.; Thurn, H.

doi:10.1021/j100368a056

Cited by 65 publications

(63 citation statements)

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“…Electric birefringent measurements were performed as previously outlined in (34,35). The examined mixtures were placed in a 5-cm quartz spectrophotometer cuvet with stainless steel electrodes.…”

Section: Methodsmentioning

confidence: 99%

Electrorheological Effects in Lecithin Organogels with Water and Glycerol

Shchipunov

Dürrschmidt

Hoffmann

1999

Journal of Colloid and Interface Science

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Section: Methodsmentioning

confidence: 99%

Electrorheological Effects in Lecithin Organogels with Water and Glycerol

Shchipunov

Dürrschmidt

Hoffmann

1999

Journal of Colloid and Interface Science

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“…This is called the normal birefringence of charged rods. Anomalous birefringence, meaning perpendicular orientation of rods, is typically obtained for long particles, low salt concentration or particle concentrations beyond mutual overlap [246,245,248] and at present only partially understood [249]. It seems likely that the anomalous electric birefringence of charged polymers is caused by the above-mentioned hydrodynamic orientation in cases when the typically much stronger electric polarizability orientation is weakened due to the overlap or evaporation of counterion clouds.…”

Section: Polyelectrolytes In Electric Fieldsmentioning

confidence: 99%

Statics and dynamics of strongly charged soft matter

Boroudjerdi¹,

Kim²,

Naji³

et al. 2005

Physics Reports

339

523

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Soft matter materials, such as polymers, membranes, proteins, are often electrically charged. This makes them water soluble, which is of great importance in technological application and a prerequisite for biological function. We discuss a few static and dynamic systems that are dominated by charge effects. One class comprises complexation between oppositely charged objects, for example the adsorption of charged ions or charged polymers on oppositely charged substrates of different geometry. Here the main questions are whether adsorption occurs and what the effective charge of the resulting complex is. We explicitly discuss the adsorption behavior of polyelectrolytes on substrates of planar, cylindrical and spherical geometry with specific reference to DNA adsorption on supported charged lipid layers, DNA adsorption on oppositely charged cylindrical dendro-polymers, and DNA binding on globular histone proteins, respectively. In all these systems salt plays an important role, and some of the important features can already be obtained on the linear Debye-Hückel level. The second class comprises effective interactions between similarly charged objects. Here the main theme is to understand the experimental finding that similarly and highly charged bodies attract each other in the presence of multi-valent counterions. This is demonstrated using field-theoretic arguments as well as Monte-Carlo simulations for the case of two homogeneously charged bodies. Realistic surfaces, on the other hand, are corrugated and also exhibit modulated charge distributions, which is important for static properties such as the counterion-density distribution, but has even more pronounced consequences for dynamic properties such as the counterion mobility. More pronounced dynamic effects are obtained with highly condensed charged systems in strong electric fields. Likewise, an electrostatically collapsed highly charged polymer is unfolded and oriented in strong electric fields. All charged systems occur in water, and water by itself is not a very well understood material. At the end of this review, we give a very brief and incomplete account of the behavior of water at planar surfaces. The coupling between water structure and charge effects is largely unexplored, and a few directions for future research are sketched. On an even more nanoscopic level, we demonstrate using ab-initio methods that specific interactions between oppositely charged groups (which occur when their electron orbitals start to overlap) are important and cause ion-specific effects that have recently moved into the focus of interest.

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“…Here again, theoretical methods used in electrostatics apply. Blake [37] developed the image method for hydrodynamics near a plane and obtained the Green's function in the presence of a no-slip planar boundary at z = 0 as (12) where r = r i − r j and R = r i − r j and j is the image with respect to the plane z = 0 (see Fig. 1).…”

Section: Hydrodynamic Interactions Near a No-slip Surfacementioning

confidence: 99%

Hydrodynamic effects in driven soft matter

et al. 2006

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Recent theoretical works exploring the hydrodynamics of soft material in non-equilibrium situations are reviewed. We discuss the role of hydrodynamic interactions for three different systems: i) the deformation and orientation of sedimenting semiflexible polymers, ii) the propulsion and force-rectification with a nano-machine realized by a rotating elastic rod, and iii) the deformation of a brush made of grafted semiflexible polymers in shear flows. In all these examples deformable polymers are subject to various hydrodynamic flows and hydrodynamic interactions. Perfect stiff nano-cylinders are known to show no orientational effects as they sediment through a viscous fluid, but it is the coupling between elasticity and hydrodynamic torques that leads to an orientation perpendicular to the direction of sedimentation. Likewise, a rotating stiff rod does not lead to a net propulsion in the Stokes limit, but if bending is allowed an effective thrust develops whose strength and direction is independent of the sense of rotation and thus acts as a rectification device. Lastly, surface-anchored polymers are deformed by shear flows, which modifies the effective hydrodynamic boundary condition in a non-linear fashion. All these results are obtained with hydrodynamic Brownian dynamics simulation techniques, as appropriate for dilute systems. Scaling analyses are presented when possible. The common theme is the interaction between elasticity of soft matter and hydrodynamics, which can lead to qualitatively new effects.

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Anomalous behavior of micellar solutions in electric birefringence measurements

Cited by 65 publications

References 0 publications

Electrorheological Effects in Lecithin Organogels with Water and Glycerol

Electrorheological Effects in Lecithin Organogels with Water and Glycerol

Statics and dynamics of strongly charged soft matter

Hydrodynamic effects in driven soft matter

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