Mechanics of Nano-Honeycomb Silica Structures: Size-Dependent Brittle-to-Ductile Transition

Porous silica structures with intricate design patterns form the exoskeleton of diatoms, a large class of microscopic mineralized algae, whose structural features have been observed to exist down to nanoscale dimensions. Nanoscale patterned porous silica structures have also been manufactured for the use in optical systems, catalysts, and semiconductor nanolithography. The mechanical properties of these porous structures at the nanoscale are a subject of great interest for potential technological and biomimetic applications in the context of new classes of multifunctional materials. Previous studies have established the emergence of enhanced toughness and ductility in nanoporous crystalline silica structures over bulk silica. The authors undertake molecular dynamics simulations and theoretical size-scaling studies of elasticity and strength of a simple model of generic nanoporous silica structures, used to establish a theoretical model for the detailed mechanisms behind their improved properties, and show...