Strong hybrid cellular/lamellar ceramic/polymer composites via emulsification freeze casting

Abstract

Despite their unremarkable constituents, natural materials, with their hybrid hierarchical structure, possess exceptional mechanical properties. The hybrid hierarchical structure typically comprises two or more distinct phases such as lamellar, gradient, tubular, and cellular form. An oil‐in‐water emulsion freeze casting method is devised to create composite materials with a bio‐inspired hybrid cellular/lamellar structure. The impact of two types of binders on the microstructure, namely, polyvinyl alcohol and F127, and their correlation with the mechanical properties of the composites were investigated. Samples fabricated with a 5 wt.% F127 emulsification slurry exhibited an “H”‐shaped cellular/lamellar structure and achieved compressive strength and specific energy absorption of about 360 MPa and 37 kJ/kg, which are noteworthy considering their ceramic and epoxy composition. Finite element analyses were then conducted to reveal how mechanical load distribution between the different phases of the composites and the influence of microstructure on fracture paths can lead to enhancement in mechanical properties.