Stretched-exponential relaxation of electric birefringence in complex liquids

Degiorgio, Vittorio; Piazza, Roberto; Mantegazza, Francesco; Bellini, Tommaso

doi:10.1088/0953-8984/2/s/007

Cited by 18 publications

(9 citation statements)

References 20 publications

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“…The impact of polydispersity on the rotational diffusion has been deeply investigated in the past. In refs ( 52 and 67 ) it was demonstrated that the stretched exponential function accurately simulates the orientational randomization process of polydisperse systems. In fact, the characterization of the size with electric birefringence experiments of the particles studied in the present work has already been successfully used in refs ( 43 and 58 ) where it was shown that the particle size is well predicted by the rotational diffusion decay fitted to a stretched exponential.…”

Section: Resultsmentioning

confidence: 99%

Electro-optical Study of the Anomalous Rotational Diffusion in Polymer Solutions

et al. 2023

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Brownian diffusion of spherical nanoparticles is usually exploited to ascertain the rheological properties of complex media. However, the behavior of the tracer particles is affected by a number of phenomena linked to the interplay between the dynamics of the particles and polymer coils. For this reason, the characteristic lengths of the dispersed entities, depletion phenomena, and the presence of sticking conditions have been observed to affect the translational diffusion of the probes. On the other hand, the retardation effect of the host fluid on the rotational diffusion of nonspherical particles is less understood. We explore the possibility of studying this phenomenon by analyzing the electro-orientation of the particles in different scenarios in which we vary the ratio between the particle and polymer characteristic size, and the geometry of the particles, including both elongated and oblate shapes. We find that the Stokes–Einstein relation only applies if the radius of gyration of the polymer is much shorter than the particle size and when some repulsive interaction between both is present.

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Section: Resultsmentioning

confidence: 99%

Electro-optical Study of the Anomalous Rotational Diffusion in Polymer Solutions

et al. 2023

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“…Electric birefringence has been extensively used as a technique for the characterization of rotational diffusion of suspended nanoparticles, providing excellent results in the determination of particle dimensions. ,− In order to study the diffusion coefficient of the AuNRs from EB measurements, two approaches are available. The first one consists of analysis of the decay of the birefringence after the electric field is turned off.…”

Section: Resultsmentioning

confidence: 99%

Electric Birefringence of Gold Nanorods: Effect of Surfactant Coating

et al. 2019

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The optical and electrical properties of gold nanorods, together with the possibility to control their orientation, have proven crucial for their use in applications such as metamaterials, nanoelectronics, molecular devices, or particle traps. When the rods are immersed in liquid media, their orientation can be controlled by electric fields and monitored by electro-optical techniques. We demonstrate that both the charged surfactant layer that surrounds the particle and the conducting core affect electro-orientation. An interpretation in light of a soft particle polarization model is provided: below 1 MHz, ions in the surfactant layer produce a large dipole accounting for the response of the system. With this model, we obtain the charge density of the coating and the conductivity of the metallic core. The results are contrasted with electrophoresis data. We also demonstrate that the presence of surfactant micelles in the medium slows down the dynamics of the system.

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“…With this motivation, in this work we analyse the suitability of three different birefringence-based approaches for particle size determination: the stretched exponential (SE) 40 , 41 , multi-exponential (ME) 42 and Watson-Jennings (WJ) 43 methods. From the analysis of a single birefringence decay, the former enables the determination of the average particle dimensions, and the latter two can provide a complete size distribution of the particles in the sample.…”

Section: Electric Birefringence-based Methods For Size Characterizatimentioning

confidence: 99%

“…The decay of the electric birefringence of a polydisperse sample is expected to be, under reasonable assumptions, in the form of a stretched exponential function 40 , 41 where Δ n 0 is the initial value of the birefringence, α a polydispersity factor and τ a characteristic decay time, which can be related to the average rotational diffusion coefficient of the particles as .…”

Section: Electric Birefringence-based Methods For Size Characterizatimentioning

confidence: 99%

Determination of the size distribution of non-spherical nanoparticles by electric birefringence-based methods

Arenas-Guerrero

Delgado

Donovan

et al. 2018

Sci Rep

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The in situ determination of the size distribution of dispersed non-spherical nanoparticles is an essential characterization tool for the investigation and use of colloidal suspensions. In this work, we test a size characterization method based on the measurement of the transient behaviour of the birefringence induced in the dispersions by pulsed electric fields. The specific shape of such relaxations depends on the distribution of the rotational diffusion coefficient of the suspended particles. We analyse the measured transient birefringence with three approaches: the stretched-exponential, Watson-Jennings, and multi-exponential methods. These are applied to six different types of rod-like and planar particles: PTFE rods, goethite needles, single- and double-walled carbon nanotubes, sodium montmorillonite particles and gibbsite platelets. The results are compared to electron microscopy and dynamic light scattering measurements. The methods here considered provide good or excellent results in all cases, proving that the analysis of the transient birefringence is a powerful tool to obtain complete size distributions of non-spherical particles in suspension.

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Stretched-exponential relaxation of electric birefringence in complex liquids

Cited by 18 publications

References 20 publications

Electro-optical Study of the Anomalous Rotational Diffusion in Polymer Solutions

Electro-optical Study of the Anomalous Rotational Diffusion in Polymer Solutions

Electric Birefringence of Gold Nanorods: Effect of Surfactant Coating

Determination of the size distribution of non-spherical nanoparticles by electric birefringence-based methods

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