Inorganic-organic hybrid materials through post-synthesis modification: Impact of the treatment with azides on the mesopore structure

Autor(en)

Miriam Keppeler, Jürgen Holzbock, Johanna Akbarzadeh, Herwig Peterlik, Nicola Hüsing

Abstrakt

Hybrid, hierarchically organized, monolithic silica gels, comprising periodically arranged mesopores and a cellular macroscopic network, have been prepared through a co-condensation reaction of tetrakis(2-hydroxyethyl)orthosilicate with chloromethyl-trimethoxysilane or 3-(chloropropyl)-triethoxysilane. Subsequent conversion of the chloro groups into azido groups, by nucleophilic substitution with NaN3 in N,N-dimethylformamide, was conducted upon preservation of the monolithic structure. However, treatment with NaN3 had a strong influence on the structure in the mesoporous regime, with changes such as an increase of mesopore diameter, pore volume and lattice constants, as well as a concomitant decrease of the pore wall thickness, as confirmed by small angle X-ray scattering, transmission electron microscopy, and nitrogen sorption analysis. Similar effects were observed for unmodified silica gels by simple ageing in azide-containing media, whether a relatively small or a sterically demanding counter ion (Na+ or (H3C)4N+) was used. The structural modification did not seem to depend greatly on whether an organic aprotic solvent (N,N-dimethylformamide, 1,1,3,3-tetramethylurea, 1,3-dimethyl-2-imidazolidinone) or a protic solvent that can form hydrogen bonds, such as water, was used.

Organisation(en)

Dynamik Kondensierter Systeme

Externe Organisation(en)

Universität Ulm, Paris-Lodron Universität Salzburg

Journal

Beilstein Journal of Nanotechnology

Band

2

Seiten

486-498

Anzahl der Seiten

12

DOI

https://doi.org/10.3762/bjnano.2.52

Publikationsdatum

2011

Peer-reviewed

Ja

ÖFOS 2012

103015 Kondensierte Materie, 103018 Materialphysik

Link zum Portal

https://ucris.univie.ac.at/portal/de/publications/inorganicorganic-hybrid-materials-through-postsynthesis-modification-impact-of-the-treatment-with-azides-on-the-mesopore-structure(b47bdd6b-8c02-4aff-9767-3db6b9def624).html