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Stability and behaviour in aqueous solutions of the anionic cubic silsesquioxane substituted with tetramethylammonium

Nilsson, Emelie J. LU ; Huber, Marina ; Carlström, Göran LU orcid ; Söderman, Olle LU ; Bowron, Daniel T. ; Edler, Karen J. LU orcid and Alfredsson, Viveka LU (2019) In Physical Chemistry Chemical Physics 21(12). p.6732-6742
Abstract


The aqueous behaviour of the anionic octa-tetramethylammonium substituted cubic silsesquioxane, [N(CH
3
)
4
]
8
[Si
8
O ... (More)


The aqueous behaviour of the anionic octa-tetramethylammonium substituted cubic silsesquioxane, [N(CH
3
)
4
]
8
[Si
8
O
20
], was studied with quantitative
29
Si-NMR. This molecule partially fragments in aqueous solutions, forming several smaller entities. The most abundant silica species are the monomer, dimer, cyclic trimer, cyclic tetramer and double three-ring. Higher concentrations are required in order to prevent complete fragmentation of the cubic structure. Additives such as alcohols and tetraalkylammonium salts have a stabilising effect on the cubic silsesquioxane, unlike sodium salts that destabilise it. A high concentration solution, containing the non-fragmented molecule as well as entities resulting from fragmentations, was investigated with neutron scattering coupled with modelling, using empirical potential structure refinement (EPSR). The modelling reveals that TMA
+
ions coordinates to all different silica species, with approximately three TMA
+
per cube. These are located at the faces of the cube.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
in
Physical Chemistry Chemical Physics
volume
21
issue
12
pages
11 pages
publisher
Royal Society of Chemistry
external identifiers
  • pmid:30860209
  • scopus:85063286250
ISSN
1463-9076
DOI
10.1039/c8cp05682j
language
English
LU publication?
yes
id
4aaeb35d-6d15-4b42-a971-7216e309963e
date added to LUP
2019-04-02 14:25:47
date last changed
2025-04-04 01:01:48
@article{4aaeb35d-6d15-4b42-a971-7216e309963e,
  abstract     = {{<p><br>
                                                         The aqueous behaviour of the anionic octa-tetramethylammonium substituted cubic silsesquioxane, [N(CH                             <br>
                            <sub>3</sub><br>
                                                         )                             <br>
                            <sub>4</sub><br>
                                                         ]                             <br>
                            <sub>8</sub><br>
                                                         [Si                             <br>
                            <sub>8</sub><br>
                                                         O                             <br>
                            <sub>20</sub><br>
                                                         ], was studied with quantitative                              <br>
                            <sup>29</sup><br>
                                                         Si-NMR. This molecule partially fragments in aqueous solutions, forming several smaller entities. The most abundant silica species are the monomer, dimer, cyclic trimer, cyclic tetramer and double three-ring. Higher concentrations are required in order to prevent complete fragmentation of the cubic structure. Additives such as alcohols and tetraalkylammonium salts have a stabilising effect on the cubic silsesquioxane, unlike sodium salts that destabilise it. A high concentration solution, containing the non-fragmented molecule as well as entities resulting from fragmentations, was investigated with neutron scattering coupled with modelling, using empirical potential structure refinement (EPSR). The modelling reveals that TMA                             <br>
                            <sup>+</sup><br>
                                                          ions coordinates to all different silica species, with approximately three TMA                             <br>
                            <sup>+</sup><br>
                                                          per cube. These are located at the faces of the cube.                         <br>
                        </p>}},
  author       = {{Nilsson, Emelie J. and Huber, Marina and Carlström, Göran and Söderman, Olle and Bowron, Daniel T. and Edler, Karen J. and Alfredsson, Viveka}},
  issn         = {{1463-9076}},
  language     = {{eng}},
  number       = {{12}},
  pages        = {{6732--6742}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Physical Chemistry Chemical Physics}},
  title        = {{Stability and behaviour in aqueous solutions of the anionic cubic silsesquioxane substituted with tetramethylammonium}},
  url          = {{http://dx.doi.org/10.1039/c8cp05682j}},
  doi          = {{10.1039/c8cp05682j}},
  volume       = {{21}},
  year         = {{2019}},
}