Water-based freeze casting: Adjusting hydrophobic polymethylsiloxane for obtaining hierarchically ordered porous SiOC
Date Issued
2017-05-07
Abstract
The hydrophobic properties of methyl poly siloxane (MK) were pushed into the“hydrophilic”range by cross-linking it with (3-aminopropyl)triethoxysilane(APTES) and subsequent pyrolysis to enable water-based freeze casting. Fillerproperties are investigated by varying the ratios of MK to APTES (1:1, 1:2, 1:3,1:4, 1:5), and pyrolysis temperatures (400°C, 500°C, 600°C) for the purpose ofdetermining an optimal set of characteristics for freeze casting. Additionally, fillerselection for this purpose is facilitated by analysis of zeta potential values andvapor adsorption. It was found that water-based freeze casting with hybrid fillers,followed by a pyrolysis step (600°C-700°C), leads to a SiOC ceramic monolithwith a lamellar pore morphology and a hierarchically ordered micro/meso/macrop-ore structure. Samples pyrolyzed at 1000°C contain mesopores, having a SSA ashigh as 51.6 m2/g. The hierarchically porous structure is very promising for appli-cations involving gas or liquid transportation.
Subjects
freeze casting
;
micro/meso/macropore
;
polymer derived ceramics
;
silicon oxycarbide
;
surfacecharacteristics
;
Mimenima
Publisher
Wiley
Institution
Type
journal article
Journal/Edited collection
Band
100
Issue
5
Start page
1907
End page
1918
Page number
12
Secondary publication
Yes
Document version
Postprint
License
Alle Rechte vorbehalten
Language
English
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Name
H. Zhang, C.L. Fidelis, A. Serva, M. Wilhelm, K. Rezwan, Waterbased freez casting-adjusting hxdrophobic polymethylsiloxane_2017_accepted version.pdf
Size
4.86 MB
Format
Adobe PDF
Checksum
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