3D macroporous SiCN ceramic patterns tailored by thermally-induced deformation of template

Abstract

Three-dimensional (3D) macroporous SiCN ceramic patterns with tailored window size and pore shape were fabricated by thermal deformation of a close-packed polystyrene (PS) sphere template, which was obtained by applying consecutive capillary force and centrifugation in a packing process of a few hours. Subsequent infiltration of a viscous preceramic inorganic polymer under strong centrifugal force was followed by pyrolysis at 800 °C to decompose the sacrificial PS sphere-packed template. In this work, the window sizes among the interconnected macropores were controlled in the range of 258 to 740 nm by tailoring the shape of the packed PS spheres (diameter 1.5 μm) by annealing above the glass transition temperature (T_g) of the PS spheres for different periods. The pore shapes changed from circular to hexagonal, and the BET surface area of the samples was reduced from 443 to 337 m² g⁻¹ with a thinner network skeleton. This approach should be useful in combining a low pressure drop with high external surface area for microfluidic applications with 3D porous structures.