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3D Printing of Hierarchical Porous Silica and α‐Quartz
Author(s) -
Putz Florian,
Scherer Sebastian,
Ober Michael,
Morak Roland,
Paris Oskar,
Hüsing Nicola
Publication year - 2018
Publication title -
advanced materials technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.184
H-Index - 42
ISSN - 2365-709X
DOI - 10.1002/admt.201800060
Subject(s) - materials science , porosity , mesoporous material , nanotechnology , amorphous solid , crystallite , aqueous solution , quartz , crystallization , inkwell , chemical engineering , composite material , chemistry , crystallography , organic chemistry , engineering , metallurgy , catalysis
Abstract The ability to macroscopically shape highly porous oxide materials while concomitantly tailoring the porous network structure as desired by simple and environmentally friendly processes is of great importance in many fields. Here, a purely aqueous printing process toward deliberately shaped, hierarchically organized amorphous silica and the corresponding polycrystalline quartz analogues based on a direct ink writing process (DIW) is presented. The key to success is the careful development of the sol–gel ink, which is based on an acidic aqueous sol of a glycolated silane and structure‐directing agents. The resulting 3D (DIW) printed silica consists of a macroporous network of struts comprising hexagonally arranged mesopores on a 2D hexagonal lattice. Together with a printed porous superstructure on the millimeter scale, well‐defined pore sizes and shapes on at least three hierarchy levels can thus be fabricated. The introduction of devitrifying agents in the printed green part and subsequent heat treatment allows for the transformation of the silica structure into polycrystalline α‐quartz. While small pores (micro‐ and mesopores below 10 nm) are lost, the printed morphology and the macroporous network of struts is preserved during crystallization.