Drying of Hierarchically Organized Porous Silica Monoliths–Comparison of Evaporative and Supercritical Drying

Richard Kohns, Jorge Torres-Rodríguez, Daniel Euchler, Malina Seyffertitz, Oskar Paris, Gudrun Reichenauer, Dirk Enke, Nicola Huesing

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung


In this study, we present a detailed comparison between a conventional supercritical drying process and an evaporative drying technique for hierarchically organized porous silica gel monoliths. These gels are based on a model system synthesized by the aqueous sol–gel processing of an ethylene-glycol-modified silane, resulting in a cellular, macroporous, strut-based network comprising anisotropic, periodically arranged mesopores formed by microporous amorphous silica. The effect of the two drying procedures on the pore properties (specific surface area, pore volume, and pore widths) and on the shrinkage of the monolith is evaluated through a comprehensive characterization by using nitrogen physisorption, electron microscopy, and small-angle X-ray scattering. It can clearly be demonstrated that for the hierarchically organized porous solids, the evaporative drying procedure can compete without the need for surface modification with the commonly applied supercritical drying in terms of the material and textural properties, such as specific surface area and pore volume. The thus obtained materials deliver a high specific surface area and exhibit overall comparable or even improved pore characteristics to monoliths prepared by supercritical drying. Additionally, the pore properties can be tailored to some extent by adjusting the drying conditions, such as temperature.
FachzeitschriftGels : open access physical and chemical gels journal
PublikationsstatusVeröffentlicht - 16 Jan. 2023

Bibliographische Notiz

Funding Information:
The authors gratefully acknowledge the financial support of the Salzburg Center of Smart Materials (P1727558-IWB01), which in turn was funded by the EFRE (European Funds for Regional Development) as well as AWS (Austrian Wirtschafts Service). Moreover, the authors acknowledge that the JEOL JEM-F200 TEM instrument was funded by Interreg Österreich—Bayern 2014–2020 Programm-AB29—“Synthese, Charakterisierung und technologische Fertigungssätze für den Leichtbau” n2m “(nano-to-macro)”.

Publisher Copyright:
© 2023 by the authors.

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