Electro-optic research of polarizability dispersion in aqueous polydisperse suspensions of nanodiamonds

Петров, М. П.; Shilov, V. N.; Trusov, A. A.; Voitylov, A. V.; Vojtylov, V.V.

doi:10.1016/j.colsurfa.2016.05.087

Cited by 11 publications

(3 citation statements)

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“…The decay of the birefringence after the field is turned off because of thermal agitation, and hence it is related only to the rotational diffusion coefficient Θ of the wires. Because of the strong dependence of Θ on the particle dimensions, the analysis of the birefringence decay has been long used to determine the size of nonspherical particles in suspension. ,,,− …”

Section: Resultsmentioning

confidence: 99%

“…During the last years, this technique has been successfully applied to a number of nonspherical particles, − although only a few works have been devoted to a physical understanding of the observed phenomena. − It is well-known that the electric torque that causes the orientation is due to the dipole induced on the nanoparticle by the external electric field. However, while this effect has been extensively studied in the case of nonconducting charged particles, only a few works deal with the electric response of conducting but weakly charged nonspherical particles, as those here treated.…”

Section: Introductionmentioning

confidence: 99%

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Electro-Orientation of Silver Nanowires in Alternating Fields

et al. 2018

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In this work, we analyze the orientation of silver nanowires immersed in aqueous solutions, under the effect of alternating electric fields in a broad frequency range covering from a few Hz to several MHz. The degree of orientation is experimentally determined by electro-optical techniques, which present the advantage of measuring multiple particles at the same time. In the electro-orientation spectrum, we observe frequency dispersion in the kHz range and provide a theoretical explanation for this behavior: at high frequencies, charge separation in the nanoparticles leads to a large induced dipole responsible for strong orientation. On the other hand, at low frequencies, redistribution of the ions in solution gives rise to an induced double layer that screens the dipolar fields, and as a consequence, the degree of orientation decreases. Moreover, we measure the transient response when the electric field is switched off, from which the size distribution of the polydisperse sample is obtained. The results match those given by electron microscopy determinations.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electro-Orientation of Silver Nanowires in Alternating Fields

et al. 2018

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“…This avoids the corruption of the sample and the modification of the state of aggregation. Secondly, a very wide range of sizes, including the nano and microscale, can be studied with the same method 35 – 39 . In this technique, it is not necessary to know the concentration of the sample, as long as it can be ensured that particle interactions do not modify the rotational diffusion of the single particle.…”

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

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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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