Order induces toughness in anisotropic colloidal crystal composites

Abstract

Spatial ordering of matter elicits exotic properties sometimes absent from a material's constituents. A few highly mineralised natural materials achieve high toughness through delocalised damage, whereas synthetic particulate composites must trade toughness for mineral content. We test whether ordering the mineral phase in particulate composites through the formation of macroscopic colloidal crystals can trigger the same damage resistance found in natural materials. Our macroscopic silica rod based anisotropic colloidal crystal composites are processed fully at room temperature and pressure, reach volume fraction of mineral higher than 80%, and aided by a ductile interface, unveil plastic strain reaching 10% through the collective movement of rods and damage delocalisation over millimetres. These composites demonstrate key design rules to break free from conventionally accepted structural materials properties trade-off.