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

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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.

Detaljer

Författare
  • Martin Turesson
  • Andre Nonat
  • Christophe Labbez
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Teoretisk kemi
Originalspråkengelska
Sidor (från-till)6713-6720
TidskriftLangmuir
Volym30
Utgivningsnummer23
StatusPublished - 2014
PublikationskategoriForskning
Peer review utfördJa