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Anomalous Dynamics of Magnetic Anisotropic Colloids Studied by XPCS

Pal, Antara LU ; Zinn, Thomas; Kamal, Mohammad Arif LU ; Narayanan, Theyencheri and Schurtenberger, Peter LU (2018) In Small 14(46).
Abstract

The influence of an applied magnetic field on the collective dynamics of novel anisotropic colloidal particles whose shape resembles peanuts is reported. Being made up of hematite cores and silica shells, these micrometer-sized particles align in a direction perpendicular to the applied external magnetic field, and assemble into chains along the field direction. The anisotropic dynamics of these particles is investigated using multispeckle ultrasmall-angle X-ray photon correlation spectroscopy (USA-XPCS). The results indicate that along the direction of the magnetic field, the particle dynamics strongly depends on the length scale probed. Here, the relaxation of the intermediate scattering function follows a compressed exponential... (More)

The influence of an applied magnetic field on the collective dynamics of novel anisotropic colloidal particles whose shape resembles peanuts is reported. Being made up of hematite cores and silica shells, these micrometer-sized particles align in a direction perpendicular to the applied external magnetic field, and assemble into chains along the field direction. The anisotropic dynamics of these particles is investigated using multispeckle ultrasmall-angle X-ray photon correlation spectroscopy (USA-XPCS). The results indicate that along the direction of the magnetic field, the particle dynamics strongly depends on the length scale probed. Here, the relaxation of the intermediate scattering function follows a compressed exponential behavior at large distances, while it appears diffusive at distances comparable or smaller than the particle size. Perpendicular to the applied field (and along the direction of gravity), the experimental data can be quantitatively reproduced by a combination of an advective term originating from sedimentation and a purely diffusive one that describes the thermal diffusion of the assembled chains and individual particles.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
anisotropic collective dynamics, anisotropic magnetic colloids, magnetic field–driven self-assembly, XPCS
in
Small
volume
14
issue
46
publisher
John Wiley & Sons
external identifiers
  • scopus:85052653481
ISSN
1613-6810
DOI
10.1002/smll.201802233
language
English
LU publication?
yes
id
d5d59bc3-318f-43dd-9ba0-069ae277a9da
date added to LUP
2018-10-04 14:12:19
date last changed
2019-02-20 11:28:48
@article{d5d59bc3-318f-43dd-9ba0-069ae277a9da,
  abstract     = {<p>The influence of an applied magnetic field on the collective dynamics of novel anisotropic colloidal particles whose shape resembles peanuts is reported. Being made up of hematite cores and silica shells, these micrometer-sized particles align in a direction perpendicular to the applied external magnetic field, and assemble into chains along the field direction. The anisotropic dynamics of these particles is investigated using multispeckle ultrasmall-angle X-ray photon correlation spectroscopy (USA-XPCS). The results indicate that along the direction of the magnetic field, the particle dynamics strongly depends on the length scale probed. Here, the relaxation of the intermediate scattering function follows a compressed exponential behavior at large distances, while it appears diffusive at distances comparable or smaller than the particle size. Perpendicular to the applied field (and along the direction of gravity), the experimental data can be quantitatively reproduced by a combination of an advective term originating from sedimentation and a purely diffusive one that describes the thermal diffusion of the assembled chains and individual particles.</p>},
  articleno    = {1802233},
  author       = {Pal, Antara and Zinn, Thomas and Kamal, Mohammad Arif and Narayanan, Theyencheri and Schurtenberger, Peter},
  issn         = {1613-6810},
  keyword      = {anisotropic collective dynamics,anisotropic magnetic colloids,magnetic field–driven self-assembly,XPCS},
  language     = {eng},
  month        = {08},
  number       = {46},
  publisher    = {John Wiley & Sons},
  series       = {Small},
  title        = {Anomalous Dynamics of Magnetic Anisotropic Colloids Studied by XPCS},
  url          = {http://dx.doi.org/10.1002/smll.201802233},
  volume       = {14},
  year         = {2018},
}