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Self-Assembly of Ionic Microgels Driven by an Alternating Electric Field : Theory, Simulations, and Experiments

Colla, Thiago; Mohanty, Priti S. LU ; Nöjd, Sofi LU ; Bialik, Erik LU ; Riede, Aaron; Schurtenberger, Peter LU and Likos, Christos N. (2018) In ACS Nano 12(5). p.4321-4337
Abstract

The structural properties of a system of ionic microgels under the influence of an alternating electric field are investigated both theoretically and experimentally. This combined investigation aims to shed light on the structural transitions that can be induced by changing either the driving frequency or the strength of the applied field, which range from string-like formation along the field to crystal-like structures across the orthogonal plane. In order to highlight the physical mechanisms responsible for the observed particle self-assembly, we develop a coarse-grained description, in which effective interactions among the charged microgels are induced by both equilibrium ionic distributions and their time-averaged hydrodynamic... (More)

The structural properties of a system of ionic microgels under the influence of an alternating electric field are investigated both theoretically and experimentally. This combined investigation aims to shed light on the structural transitions that can be induced by changing either the driving frequency or the strength of the applied field, which range from string-like formation along the field to crystal-like structures across the orthogonal plane. In order to highlight the physical mechanisms responsible for the observed particle self-assembly, we develop a coarse-grained description, in which effective interactions among the charged microgels are induced by both equilibrium ionic distributions and their time-averaged hydrodynamic responses to the applied field. These contributions are modeled by the buildup of an effective dipole moment at the microgels backbones, which is partially screened by their ionic double layer. We show that this description is able to capture the structural properties of this system, allowing for very good agreement with the experimental results. The model coarse-graining parameters are indirectly obtained via the measured pair distribution functions and then further assigned with a clear physical interpretation, allowing us to highlight the main physical mechanisms accounting for the observed self-assembly behavior.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
chain formation, coarse-graining, confocal microscopy, dipoles, ionic microgels, self-assembly, soft colloids
in
ACS Nano
volume
12
issue
5
pages
17 pages
publisher
The American Chemical Society
external identifiers
  • scopus:85047402092
ISSN
1936-0851
DOI
10.1021/acsnano.7b08843
language
English
LU publication?
yes
id
ea823e5e-c84b-4975-8313-8d69225db5e4
date added to LUP
2018-06-05 12:02:52
date last changed
2019-08-14 04:17:53
@article{ea823e5e-c84b-4975-8313-8d69225db5e4,
  abstract     = {<p>The structural properties of a system of ionic microgels under the influence of an alternating electric field are investigated both theoretically and experimentally. This combined investigation aims to shed light on the structural transitions that can be induced by changing either the driving frequency or the strength of the applied field, which range from string-like formation along the field to crystal-like structures across the orthogonal plane. In order to highlight the physical mechanisms responsible for the observed particle self-assembly, we develop a coarse-grained description, in which effective interactions among the charged microgels are induced by both equilibrium ionic distributions and their time-averaged hydrodynamic responses to the applied field. These contributions are modeled by the buildup of an effective dipole moment at the microgels backbones, which is partially screened by their ionic double layer. We show that this description is able to capture the structural properties of this system, allowing for very good agreement with the experimental results. The model coarse-graining parameters are indirectly obtained via the measured pair distribution functions and then further assigned with a clear physical interpretation, allowing us to highlight the main physical mechanisms accounting for the observed self-assembly behavior.</p>},
  author       = {Colla, Thiago and Mohanty, Priti S. and Nöjd, Sofi and Bialik, Erik and Riede, Aaron and Schurtenberger, Peter and Likos, Christos N.},
  issn         = {1936-0851},
  keyword      = {chain formation,coarse-graining,confocal microscopy,dipoles,ionic microgels,self-assembly,soft colloids},
  language     = {eng},
  month        = {05},
  number       = {5},
  pages        = {4321--4337},
  publisher    = {The American Chemical Society},
  series       = {ACS Nano},
  title        = {Self-Assembly of Ionic Microgels Driven by an Alternating Electric Field : Theory, Simulations, and Experiments},
  url          = {http://dx.doi.org/10.1021/acsnano.7b08843},
  volume       = {12},
  year         = {2018},
}