Freezing as a Path to Build Complex Composites

Abstract

Materials that are strong, ultralightweight, and tough are in demand for a range of applications, requiring architectures and components carefully designed from the micrometer down to the nanometer scale. Nacre, a structure found in many molluscan shells, and bone are frequently used as examples for how nature achieves this through hybrid organic-inorganic composites. Unfortunately, it has proven extremely difficult to transcribe nacre-like clever designs into synthetic materials, partly because their intricate structures need to be replicated at several length scales. We demonstrate how the physics of ice formation can be used to develop sophisticated porous and layered-hybrid materials, including artificial bone, ceramic-metal composites, and porous scaffolds for osseous tissue regeneration with strengths up to four times higher than those of materials currently used for implantation.

Biomimetic superelastic graphene-based cellular monoliths

“…Subsequent sublimation of ice results in the formation of a porous solid material. Freeze casting has been successfully adopted to synthesize a variety of porous ceramic, metallic, polymeric and composite materials, including carbon nanotubes or graphene-based polymer composites 18,[30][31][32][33] . Although previous research on freeze casting has been centred on polymers and spherical particles 28,29 , we were particularly interested in studying how 2D graphene sheets interact with anisotropic ice crystal growth without the interference of other polymer or surfactant additives.…”

“…In conjunction with the anisotropic structure of GO, the principle of the freeze-casting process that has previously been proposed for other nanoparticle suspensions 30,31 can be extended to elucidate the formation of such a unique cellular structure. As schematically illustrated in Fig.…”

Structure and mechanical properties of selected protective systems in marine organisms

“…Given its presence in the bones and teeth of humans, it has garnered a significant amount of research in the biomedical field, producing a number of bioinspired designs with a focus on biomedical materials and implants [9,[57][58][59][60][61]. Biogenic hydroxyapatite often forms around a collagen scaffold that directs growth (Fig.…”

A novel biomimetic approach to the design of high-performance ceramic–metal composites

“…Lamellar alumina scaffolds were fabricated in bulk form by freeze-casting (Fukasawa et al 2001;Araki & Halloran 2004;Deville et al 2006;Deville 2008;Waschkies et al 2009) a water-based suspension of sub-micrometre alumina powder (solid content 50 wt%). Sucrose (4 wt%) was added to the suspension in order to ensure the formation of fine ceramic lamellae with a characteristic microscopic roughness ).…”

“…Recently, a new class of bioinspired ceramic-based materials have been developed (Deville et al 2006;Munch et al 2008) by controlled freezing of ceramic-based suspensions in water, termed 'ice-templating' or freeze-casting (Deville et al 2006); this technique provides a means to mimic natural structural designs over several length scales. The approach uses the freezing properties of water to make ice/ceramic powder suspensions; when the water is sublimed out, the remaining ceramic scaffold represents the 'negative' of the ice structure.…”