Abstract
The preparation of ordered macroporous SiCN ceramics has attracted significant interest and is an attractive area for various applications, e.g., in the fields of catalysis, gas adsorption, or membranes. Non-oxidic ceramics, such as SiCN, own a great stability based on the covalent bonds between the containing elements, which leads to interesting properties concerning resistance and stability at high temperature. Their peculiar properties have become more and more important for a manifold of applications, like catalysis or separation processes, at high temperatures. Within this work, a feasible approach for the preparation of ordered porous materials by taking advantage of polymer-derived ceramics is presented. To gain access to free-standing films consisting of porous ceramic materials, the combination of monodisperse organic polymer-based colloids with diameters of 130 nm and 180 nm featuring a processable preceramic polymer is essential. For this purpose, the tailored design of hybrid organic/inorganic particles featuring anchoring sites for a preceramic polymer in the soft shell material is developed. Moreover, polymer-based core particles are used as sacrificial template for the generation of pores, while the preceramic shell polymer can be converted to the ceramic matrix after thermal treatment. Two different routes for the polymer particles, which can be obtained by emulsion polymerization, are followed for covalently linking the preceramic polysilazane Durazane1800 (Merck, Germany): (i) Free radical polymerization and (ii) atom transfer radical polymerization (ATRP) conditions. These hybrid hard core/soft shell particles can be processed via the so-called melt-shear organization for the one-step preparation of free-standing particle films. A major advantage of this technique is the absence of any solvent or dispersion medium, enabling the core particles to merge into ordered particle stacks based on the soft preceramic shell. Subsequent ceramization of the colloidal crystal films leads to core particle degradation and transformation into porous ceramics with ceramic yields of 18–54%.
Highlights
Polymer-derived ceramics (PDCs) and nanocomposites emerged in the last decades as high-potential materials with unique phase compositions and microstructures, as well as outstanding structural and functional properties [1,2,3,4,5,6,7,8]
We report, for the first time, the covalent binding of the preceramic polysilazane Durazane1800 to the surface of organic template particles, which are accessible via emulsion polymerization
For the blend system, the organic particles were observed in the middle of the film, while the viscous polysilazane flowed to the outside of the film
Summary
Polymer-derived ceramics (PDCs) and nanocomposites emerged in the last decades as high-potential materials with unique phase compositions and microstructures, as well as outstanding structural and functional properties [1,2,3,4,5,6,7,8]. Their preparative access from liquid or soluble preceramic. Ordered porosity may be achieved by (i) providing a stable colloidal mixture consisting of preceramic polymer and fillers, (ii) slow evaporation of the solvent, which occurs accompanied by a close(st) packed assemblage of the filler particles, and subsequently (iii) thermal treatment leading to ceramization of the preceramic polymer and the burn-out of the filler particles [2,35,42,43]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
