Herein we report for the first time the synthesis of three-dimensional scaffolds in the binary system SiO2-P2O5 exhibiting different scales of porosity: (i) highly ordered mesopores with diameters of ca. 4 nm; (ii) macropores with diameters in the 30-80 μm range with interconnections of ca. 2-4 and 8-9 μm; and (iii) ultra-large macropores of ca. 400 μm. The hierarchical porosity of the resulting scaffolds makes them suitable for bone tissue engineering applications. The chemical nature and mesoporosity of these matrices would allow these scaffolds to act as local controlled delivery systems of biologically active molecules, such as certain drugs to treat bone pathologies. The synthetic method consists of the combination of a single-step sol-gel route in the presence of a surfactant as the mesostructure directing agent and a biomacromolecular polymer such as methylcellulose as the macrostructure template followed by rapid prototyping technique. An exhaustive study of the aging process as well as of the rheological properties of the slurry after methylcellulose addition has been carried out to obtain hierarchical meso-macroporosity. This study allows the establishment of the time period in which the slurry presents appropriate viscosity to be extruded during the rapid prototyping once the ink is prepared. The setting up of this manufacture process at the laboratory level is important from the industrial point of view when the large-scale production of scaffolds for bone tissue repair and regeneration is targeted.
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http://dx.doi.org/10.1016/j.actbio.2010.10.006 | DOI Listing |
Langmuir
August 2022
Institute of Physical Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, Giessen D-35392, Germany.
The impact of synthesis parameters and structural properties, respectively, on mechanical properties of porous materials on different structural levels provides valuable information for designing materials for specific applications. Within this study, we apply two nonstandard approaches for determining the mechanical properties of the mesoporous backbone phase in a series of disordered SiO-based monolithic materials possessing hierarchical meso-macroporosity, that is, deformation upon mercury porosimetry and in situ dilatometry during nitrogen adsorption analysis. By using ordered porous model materials, the latter method has been recently proven to provide reliable mechanical moduli.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2020
Nanotechnology Research Laboratory Research School of Electrical, Energy, and Materials Engineering Australian National University Canberra 2601 Australia.
The structuring of the metal-organic framework material ZIF-8 as films and membranes through the vapor-phase conversion of ZnO fractal nanoparticle networks is reported. The extrinsic porosity of the resulting materials can be tuned from 4% to 66%, and the film thickness can be controlled from 80 nm to 0.23 mm, for areas >100 cm.
View Article and Find Full Text PDFACS Omega
April 2020
Laboratory of Heterogeneous Catalysis, Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14977-16363 Tehran, Iran.
Crystallization of as-mesocellular silica foam (as-MCF) into TS-1 zeolites by conventional hydrothermal and dense-gel routes is reported. The TS-1 synthesized through the dense-gel route (TS-1-) showed higher meso-macroporosity (0.311 0.
View Article and Find Full Text PDFACS Appl Mater Interfaces
April 2016
Helmholtz Institute Ulm for Electrochemical Energy Storage, Helmholtzstrasse 11, 89081 Ulm, Germany.
Nitrogen-rich carbon with both a turbostratic microstructure and meso/macroporosity was prepared by hard templating through pyrolysis of a tricyanomethanide-based ionic liquid in the voids of a silica monolith template. This multifunctional carbon not only is a promising anode candidate for long-life lithium-ion batteries but also shows favorable properties as anode and cathode host material owing to a high nitrogen content (>8% after carbonization at 900 °C). To demonstrate the latter, the hierarchical carbon was melt-infiltrated with sulfur as well as coated by atomic layer deposition (ALD) of anatase TiO2, both of which led to high-quality nanocomposites.
View Article and Find Full Text PDFChem Soc Rev
October 2015
Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, Netherlands.
Recently the concept of hierarchical zeolites invoked more explicit attention to enhanced accessibility of zeolites. By realizing additional meso-/macroporosity with the intrinsic microporosity of zeolites, a hierarchical pore system arises which facilitates mass transport while maintaining the zeolite shape selectivity. A great number of synthesis strategies have been developed for tailoring the pore architecture of hierarchical zeolites.
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