Hydrodynamic properties of rodlike and disklike particles in dilute solution

The translational and rotational diffusion of a series of gold nanorods with low aspect ratio was investigated by dynamic light scattering (DLS). It is shown that the translational and the rotational diffusion coefficient can be determined because the particle shape causes an anisotropy of the polarizability. This gives rise to two clearly distinguishable relaxation modes in the time correlation function of the scattered light. The particle length and aspect ratio were determined independently by transmission electron microscopy (TEM). Using a hydrodynamic model, these geometrical parameters were converted to diffusion constants, which agree well with the values determined by DLS. Additionally it is possible to obtain an estimate of the particles aspect ratio from the amplitude ratio of the two relaxation modes.

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“…Since this requirement is not fulfilled for our Au-rods, we chose to apply the expression by Ortega and de la Torre [38] …”

Section: Resultsmentioning

confidence: 99%

Dynamic Light Scattering of Short Au Rods with Low Aspect Ratios

et al. 2007

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“…(2) is the diffusive flux of entropic origin corresponding to Fick's law. The quantity D stands for the translational diffusion coefficient of a cylindrical rigid polymer [38,39] given by…”

Section: A Electrohydrodynamically Augmented Smoluchowski Equationmentioning

confidence: 99%

Controlling polymer capture and translocation by electrostatic polymer-pore interactions

Buyukdagli

Ala-Nissilä

2017

The Journal of Chemical Physics

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Polymer translocation experiments typically involve anionic polyelectrolytes such as DNA molecules driven through negatively charged nanopores. Quantitative modelling of polymer capture to the nanopore followed by translocation therefore necessitates the consideration of the electrostatic barrier resulting from like-charge polymer-pore interactions. To this end, in this work we couple mean-field level electrohydrodynamic equations with the Smoluchowski formalism to characterize the interplay between the electrostatic barrier, the electrophoretic drift, and the electro-osmotic liquid flow. In particular, we find that due to distinct ion density regimes where the salt screening of the drift and barrier effects occur, there exists a characteristic salt concentration maximizing the probability of barrier-limited polymer capture into the pore. We also show that in the barrierdominated regime, the polymer translocation time τ increases exponentially with the membrane charge and decays exponentially fast with the pore radius and the salt concentration. These results suggest that the alteration of these parameters in the barrier-driven regime can be an efficient way to control the duration of the translocation process and facilitate more accurate measurements of the ionic current signal in the pore.

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“…The corresponding line has two independent parameters: a slope and an intercept, which relate to the translational and rotational diffusivities, which in turn are related to the dimensions of the tCNCs. The diffusion coefficients of long and straight rods can generally be expressed by a common form 26,27 (12) where L and W are the length and width, and L/W is the aspect ratio. Equations 11 and 12 do not take into account whether the ends of the rods are flat or round, which in fact can affect Brownian dynamics when the aspect ratio is small.…”

Section: ■ Resultsmentioning

confidence: 99%

Speckle-Visibility Spectroscopy of Depolarized Dynamic Light Scattering

et al. 2017

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We show that the statistical analysis of photon counts in depolarized dynamic light scattering experiments allows for the accurate characterization of the rotational Brownian dynamics of particles. Unlike photon correlation spectroscopy, the technique is accurate even at low temporal resolution and enables discontinuous data acquisition, which offers several advantages. To demonstrate the usefulness of the method, we present a case study in which we analyze aqueous suspensions of tunicate cellulose nanocrystals and silica particles, and discuss aspects that are specific to particle sizing.

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Hydrodynamic properties of rodlike and disklike particles in dilute solution

Cited by 283 publications

References 31 publications

Dynamic Light Scattering of Short Au Rods with Low Aspect Ratios

Dynamic Light Scattering of Short Au Rods with Low Aspect Ratios

Controlling polymer capture and translocation by electrostatic polymer-pore interactions

Speckle-Visibility Spectroscopy of Depolarized Dynamic Light Scattering

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