Exploring hybrid imogolite nanotubes formation via Si/Al stoichiometry control

Pierre Picot (1) , Yuan Yuan Liao (1) , Elodie Barruet (1) , Frédéric Gobeaux (1) , Thibaud Coradin (2) , Antoine Thill (1)

1 LIONS - Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire
2 LCMCP-MATBIO - Matériaux et Biologie

Hybrid imogolite aluminosilicate nanotubes with methylated internal surface can be obtained by introduction of the corresponding organosilane during their synthesis. However, similarly to pristine imogolite, a number of side-products, including proto-imogolite (open-imoLS), allophanes and aluminum hydroxides, are formed, that ultimately impact on the properties of the dispersions. In order to minimize the proportion of these side-products, we have here systematically explored the impact of the initial Si/Al ratio on the content of hybrid imogolite dispersions before and after dialysis. By combining cryo-TEM, ICPMS, IR spectroscopy and Small Angle X-ray Scattering, we evidenced that the Si/Al ratio has a large impact on the formation of aluminum hydroxides that can be minimized with a slight excess of Si precursor. However, a large excess of Si is detrimental to the reaction yield leading to an important proportion of proto-imogolite. We propose that the optimal Si/Al ratio of ca. 0.6 can both minimize the proportion of aluminum hydroxides and proto-imogolite. These results suggest that the dynamic and therefore reactive character of Imogolite dispersions may have been so far underlooked.

Domaines: Matériaux

Pierre Picot, Yuan Yuan Liao, Elodie Barruet, Frédéric Gobeaux, Thibaud Coradin, et al.. Exploring hybrid imogolite nanotubes formation via Si/Al stoichiometry control. Langmuir, 2018, ⟨10.1021/acs.langmuir.8b01075⟩. ⟨cea-01895086⟩