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Université de Fribourg

Taylor dispersion of inorganic nanoparticles and comparison to dynamic light scattering and transmission electron microscopy

A.Urban, Dominic ; M.Milosevic, Ana ; Bossert, David ; Crippa, Federica ; L.Moore, Thomas ; Geers, Christoph ; Balog, Sandor ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Colloid and Interface Science Communications, 2018, vol. 22, p. 29–33

Taylor dispersion analysis (TDA) is an analytical method that has so far mainly been utilized to determine the diffusion coefficient of small molecules, and proteins. Due to increasing interest in nanoscience, some research has been done on the applicability of TDA towards characterizing nanoparticles. This work aims to expand this knowledge and give insight into the range for which TDA can...

Université de Fribourg

Hypothesis test of the photon count distribution for dust discrimination in dynamic light scattering

Bossert, David ; Crippa, Federica ; Petri-Fink, Alke ; Balog, Sandor

In: Analytical Chemistry, 2018, vol. 90, no. 6, p. 3656–3660

Users of dynamic light scattering (DLS) are challenged when a sample of nanoparticles (NPs) contains dust. This is a frequently inevitable scenario and a major problem that critically affects the reproducibility and accuracy of DLS measurements. Current methods approach this problem via photon correlation spectroscopy, but remedy exists only for a few special cases. We introduce here a...

Université de Fribourg

Hybrid magnetic iron oxide nanoparticles with tunable field-directed self-assembly

Malik, Vikash ; Pal, Antara ; Pravaz, Olivier ; Crassous, Jérôme J. ; Granville, Simon ; Grobéty, Bernard ; Hirt, Ann M. ; Dietsch, Hervé ; Schurtenberger, Peter

In: Nanoscale, 2017, vol. 9, no. 38, p. 14405-14413

We describe the synthesis of hybrid magnetic ellipsoidal nanoparticles that consist of a mixture of two different iron oxide phases, hematite (α-Fe2O3) and maghemite (γ- Fe2O3), and characterize their magnetic field-driven self-assembly. We demonstrate that the relative amount of the two phases can be adjusted in a continuous way by varying the reaction time during the synthesis, leading to...

Université de Fribourg

Taylor dispersion of nanoparticles

Urban, Dominic A. ; Milosevic, Ana M. ; Crippa, Federica ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Journal of Nanoparticle Research, 2017, vol. 19, no. 8, p. 287

The ability to detect and accurately characterize particles is required by many fields of nanotechnology, including materials science, nanotoxicology, and nanomedicine. Among the most relevant physicochemical properties of nanoparticles, size and the related surface-to-volume ratio are fundamental ones. Taylor dispersion combines three independent phenomena to determine particle size: optical...

Université de Fribourg

Speckle-visibility spectroscopy of depolarized dynamic light scattering

Bossert, David ; Natterodt, Jens ; Urban, Dominic A. ; Weder, Christoph ; Petri-Fink, Alke

In: The Journal of Physical Chemistry B, 2017, vol. 121, no. 33, p. 7999–8007

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...