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Stability of Negatively Charged Platelets in Calcium-Rich Anionic Copolymer Solutions

Turesson, Martin LU ; Nonat, Andre and Labbez, Christophe (2014) In Langmuir 30(23). p.6713-6720
Abstract
Controlling the stability of anisotropic particles is key to the development of advanced materials. Here, we report an investigation, by means of mesoscale molecular dynamics simulations, of the stability and structural change of calcium-rich dispersions containing negatively charged nanoplatelets, neutralized by calcium counterions, in the presence of either comb copolymers composed of anionic backbones with attached neutral side chains or anionic-neutral linear block copolymers. In agreement with experimental observations, small stacks of platelets (tactoids) are formed, which are greatly stabilized in the presence of copolymers. In the absence of polymers, tactoids will grow and aggregate strongly due to large attractive Ca2+-Ca2+... (More)
Controlling the stability of anisotropic particles is key to the development of advanced materials. Here, we report an investigation, by means of mesoscale molecular dynamics simulations, of the stability and structural change of calcium-rich dispersions containing negatively charged nanoplatelets, neutralized by calcium counterions, in the presence of either comb copolymers composed of anionic backbones with attached neutral side chains or anionic-neutral linear block copolymers. In agreement with experimental observations, small stacks of platelets (tactoids) are formed, which are greatly stabilized in the presence of copolymers. In the absence of polymers, tactoids will grow and aggregate strongly due to large attractive Ca2+-Ca2+ correlation forces. Unlike comb copolymers which only adsorb on the external surfaces, block copolymers are found to intercalate between the platelets. The present results show that the stabilization is the result of a free energy barrier induced by the excluded volume of hydrophilic chains, while the intercalation is due to bridging forces. More generally, the results shed new light on the recent finding of the first hybrid cementitious mesocrystal. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
30
issue
23
pages
6713 - 6720
publisher
The American Chemical Society
external identifiers
  • wos:000337644200010
  • scopus:84902578585
ISSN
0743-7463
DOI
10.1021/la501228w
language
English
LU publication?
yes
id
1b9b88ec-fe95-43a6-96c9-9128aafeaffd (old id 4609567)
date added to LUP
2014-08-25 15:41:28
date last changed
2017-09-24 03:06:11
@article{1b9b88ec-fe95-43a6-96c9-9128aafeaffd,
  abstract     = {Controlling the stability of anisotropic particles is key to the development of advanced materials. Here, we report an investigation, by means of mesoscale molecular dynamics simulations, of the stability and structural change of calcium-rich dispersions containing negatively charged nanoplatelets, neutralized by calcium counterions, in the presence of either comb copolymers composed of anionic backbones with attached neutral side chains or anionic-neutral linear block copolymers. In agreement with experimental observations, small stacks of platelets (tactoids) are formed, which are greatly stabilized in the presence of copolymers. In the absence of polymers, tactoids will grow and aggregate strongly due to large attractive Ca2+-Ca2+ correlation forces. Unlike comb copolymers which only adsorb on the external surfaces, block copolymers are found to intercalate between the platelets. The present results show that the stabilization is the result of a free energy barrier induced by the excluded volume of hydrophilic chains, while the intercalation is due to bridging forces. More generally, the results shed new light on the recent finding of the first hybrid cementitious mesocrystal.},
  author       = {Turesson, Martin and Nonat, Andre and Labbez, Christophe},
  issn         = {0743-7463},
  language     = {eng},
  number       = {23},
  pages        = {6713--6720},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Stability of Negatively Charged Platelets in Calcium-Rich Anionic Copolymer Solutions},
  url          = {http://dx.doi.org/10.1021/la501228w},
  volume       = {30},
  year         = {2014},
}