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

文献情報

出版日 2019-03-04

DOI 10.1039/C8CP05682J

インパクトファクター 3.676

著者

Emelie J. Nilsson, Marina Huber, Göran Carlström, Olle Söderman, Daniel T. Bowron, Viveka Alfredsson

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要旨

The aqueous behaviour of the anionic octa-tetramethylammonium substituted cubic silsesquioxane, [N(CH3)4]8[Si8O20], was studied with quantitative 29Si-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.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

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