Microstructural and Swelling Properties of Ca and Na Montmorillonite: (In Situ) Observations with Cryo-TEM and SAXS
Segad, Mo LU ; Hanski, S. ; Olsson, Ulf LU
; Ruokolainen, J.
; Åkesson, Torbjörn
LU
and Jönsson, Bo
LU
(2012)
In Journal of Physical Chemistry C
116(13).
p.7596-7601
- Abstract
- Aqueous dispersions of pure sodium and calcium smectite clays with platelet sizes on the order of a few hundred nanometers were characterized using a combination of cryo-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS). With monovalent sodium counterions the clay is dispersed as individual platelets, as seen by cryo-TEM, that order into a nematic phase. From SAXS a one-dimensional swelling of the day in water is observed with the characteristic spacing h(s) = delta/phi(c), where h(s) is the separation between the platelets, delta = 1 nm is the effective platelet thickness, and phi(c) is the clay volume fraction in the sample. In calcium montmorillonite, on the other hand, cryo-TEM images dearly show the... (More)
- Aqueous dispersions of pure sodium and calcium smectite clays with platelet sizes on the order of a few hundred nanometers were characterized using a combination of cryo-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS). With monovalent sodium counterions the clay is dispersed as individual platelets, as seen by cryo-TEM, that order into a nematic phase. From SAXS a one-dimensional swelling of the day in water is observed with the characteristic spacing h(s) = delta/phi(c), where h(s) is the separation between the platelets, delta = 1 nm is the effective platelet thickness, and phi(c) is the clay volume fraction in the sample. In calcium montmorillonite, on the other hand, cryo-TEM images dearly show the presence of tactoids, where the platelets have aggregated into stacks with a periodic spacing of 2 nm. From imaging a large number of tactoids the distribution function f(N) far the number of platelets per tactoid was estimated, and the average number (N) approximate to 10. The characteristic 2 nm spacing as well as the small number of platelets per tactoid was also confirmed by SAXS. The present study demonstrates that cryo-TEM, with carefully prepared specimen, is a very useful technique to characterize clay dispersions, particularly in aggregated systems. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/2587529
- author
- Segad, Mo
LU
; Hanski, S.
; Olsson, Ulf
LU
; Ruokolainen, J.
; Åkesson, Torbjörn
LU
and Jönsson, Bo
LU
- organization
- publishing date
- 2012
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Physical Chemistry C
- volume
- 116
- issue
- 13
- pages
- 7596 - 7601
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000302336700046
- scopus:84859576029
- ISSN
- 1932-7447
- DOI
- 10.1021/jp300531y
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Theoretical Chemistry (S) (011001039), Physical Chemistry 1 (S) (011001006)
- id
- 93e58ec2-3224-43cd-be66-9f0961bd67d4 (old id 2587529)
- date added to LUP
- 2016-04-01 11:11:06
- date last changed
- 2025-10-14 09:49:05
@article{93e58ec2-3224-43cd-be66-9f0961bd67d4,
abstract = {{Aqueous dispersions of pure sodium and calcium smectite clays with platelet sizes on the order of a few hundred nanometers were characterized using a combination of cryo-transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS). With monovalent sodium counterions the clay is dispersed as individual platelets, as seen by cryo-TEM, that order into a nematic phase. From SAXS a one-dimensional swelling of the day in water is observed with the characteristic spacing h(s) = delta/phi(c), where h(s) is the separation between the platelets, delta = 1 nm is the effective platelet thickness, and phi(c) is the clay volume fraction in the sample. In calcium montmorillonite, on the other hand, cryo-TEM images dearly show the presence of tactoids, where the platelets have aggregated into stacks with a periodic spacing of 2 nm. From imaging a large number of tactoids the distribution function f(N) far the number of platelets per tactoid was estimated, and the average number (N) approximate to 10. The characteristic 2 nm spacing as well as the small number of platelets per tactoid was also confirmed by SAXS. The present study demonstrates that cryo-TEM, with carefully prepared specimen, is a very useful technique to characterize clay dispersions, particularly in aggregated systems.}},
author = {{Segad, Mo and Hanski, S. and Olsson, Ulf and Ruokolainen, J. and Åkesson, Torbjörn and Jönsson, Bo}},
issn = {{1932-7447}},
language = {{eng}},
number = {{13}},
pages = {{7596--7601}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Journal of Physical Chemistry C}},
title = {{Microstructural and Swelling Properties of Ca and Na Montmorillonite: (In Situ) Observations with Cryo-TEM and SAXS}},
url = {{http://dx.doi.org/10.1021/jp300531y}},
doi = {{10.1021/jp300531y}},
volume = {{116}},
year = {{2012}},
}