Layer charge robust delamination of organo-clays

To date delamination of organo-clays is restricted to highly charged, vermiculite-type layered silicates (e.g. n-butylammonium vermiculites) while – counterintuitively – low charged, smectite-type layered silicates do not delaminate although their Coulomb interactions are much weaker. Guided by prev...

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Autores principales: Daab, Matthias, Eichstaedt, Natalie J., Edenharter, Andreas, Rosenfeldt, Sabine, Breu, Josef
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9084449/
https://www.ncbi.nlm.nih.gov/pubmed/35548394
http://dx.doi.org/10.1039/c8ra05318a
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author Daab, Matthias
Eichstaedt, Natalie J.
Edenharter, Andreas
Rosenfeldt, Sabine
Breu, Josef
author_facet Daab, Matthias
Eichstaedt, Natalie J.
Edenharter, Andreas
Rosenfeldt, Sabine
Breu, Josef
author_sort Daab, Matthias
collection PubMed
description To date delamination of organo-clays is restricted to highly charged, vermiculite-type layered silicates (e.g. n-butylammonium vermiculites) while – counterintuitively – low charged, smectite-type layered silicates do not delaminate although their Coulomb interactions are much weaker. Guided by previous findings, we now identified organo-cations that allowed for extending the delamination of organo clays to charge densities in the regime of low charged smectites as well. Upon intercalation of protonated amino-sugars like N-methyl-d-glucamine (meglumine) robust delamination of 2 : 1 layered silicates via repulsive osmotic swelling in water is achieved. This process is stable over a wide range of charge densities spanning from smectites (layer charge x ∼ 0.3 charges per formula unit Si(4)O(10)F(2), p.f.u.) to vermiculites (x ∼ 0.7 p.f.u.). It is evidenced that a combination of first, a sufficiently large charge equivalent area (bulkiness) of meglumine with second, a significant hydrophilicity of meglumine leads to swelling above a threshold d-spacing of ≳17.5 Å in moist air (98% r.h.). Hereby, electrostatic attraction is critically weakened, causing the onset of repulsive osmotic swelling which leads to utter delamination. Moreover, meglumine renders delamination tolerant to charge heterogeneities typically found in natural and synthetic clays.
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spelling pubmed-90844492022-05-10 Layer charge robust delamination of organo-clays Daab, Matthias Eichstaedt, Natalie J. Edenharter, Andreas Rosenfeldt, Sabine Breu, Josef RSC Adv Chemistry To date delamination of organo-clays is restricted to highly charged, vermiculite-type layered silicates (e.g. n-butylammonium vermiculites) while – counterintuitively – low charged, smectite-type layered silicates do not delaminate although their Coulomb interactions are much weaker. Guided by previous findings, we now identified organo-cations that allowed for extending the delamination of organo clays to charge densities in the regime of low charged smectites as well. Upon intercalation of protonated amino-sugars like N-methyl-d-glucamine (meglumine) robust delamination of 2 : 1 layered silicates via repulsive osmotic swelling in water is achieved. This process is stable over a wide range of charge densities spanning from smectites (layer charge x ∼ 0.3 charges per formula unit Si(4)O(10)F(2), p.f.u.) to vermiculites (x ∼ 0.7 p.f.u.). It is evidenced that a combination of first, a sufficiently large charge equivalent area (bulkiness) of meglumine with second, a significant hydrophilicity of meglumine leads to swelling above a threshold d-spacing of ≳17.5 Å in moist air (98% r.h.). Hereby, electrostatic attraction is critically weakened, causing the onset of repulsive osmotic swelling which leads to utter delamination. Moreover, meglumine renders delamination tolerant to charge heterogeneities typically found in natural and synthetic clays. The Royal Society of Chemistry 2018-08-13 /pmc/articles/PMC9084449/ /pubmed/35548394 http://dx.doi.org/10.1039/c8ra05318a Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/
spellingShingle Chemistry
Daab, Matthias
Eichstaedt, Natalie J.
Edenharter, Andreas
Rosenfeldt, Sabine
Breu, Josef
Layer charge robust delamination of organo-clays
title Layer charge robust delamination of organo-clays
title_full Layer charge robust delamination of organo-clays
title_fullStr Layer charge robust delamination of organo-clays
title_full_unstemmed Layer charge robust delamination of organo-clays
title_short Layer charge robust delamination of organo-clays
title_sort layer charge robust delamination of organo-clays
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9084449/
https://www.ncbi.nlm.nih.gov/pubmed/35548394
http://dx.doi.org/10.1039/c8ra05318a
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