Hierarchically Porous Ceramics by Freeze Casting of Preceramic Polymers
Graduate Student: Maninpat Naviroj

Porous ceramics are a unique class of material that can serve a diverse range of applications such as filtration, catalyst, biomedical scaffolds, and thermal barrier coatings. The function and performance of a porous material depends on its pore structure (i.e. size, shape, size distribution, connectivity, and orientation). Thus, a lot of research has been performed in order to understand how to create new porous structures, as well as how to tailor the pores accordingly, for a particular application.

Equipped with the knowledge of how to tailor pore structures to our liking, we are now able to create more complex porous materials. One way to do this is by creating materials with hierarchical porosity. Hierarchical porosity is defined as a structure that has pores of two or more different length scales. Hierarchically porosity enables a porous structure to perform more than one function and hence broaden its capabilities. For example, a structure may have micropores that increases its specific surface area, leading to higher storage or purification capacities, while also having macropores that provide effective transport of the medium as well as structural integrity.

In this project, we aim to create hierarchically porous structures from preceramic polymers, by using a technique called freeze casting. The use of preceramic polymers will enable us to study a new system of materials, while freeze casting will help us create interconnected and directional pores. Hierarchical pores can be created through various techniques, such as the use of fugitive phases, or by manipulating the processing method of the preceramic polymer. Characterization of these structures will be done through synchrotron-based methods such as X-ray computed tomography and small-angle X-ray scattering. This study will allow us to understand the structure and pore network of these novel porous ceramics.