Control of nanoenergetics through organized microstructures

Heavily doped p-type silicon substrates were etched to form thick porous layers (∼170 µm) and impregnated with magnesium perchlorate to form reactive composites. Characterization of the reactive wave propagation by high speed photography and spectroscopic methods indicated slow propagation rates between 1 and 8 m s⁻¹. Multiscale structures were formed on the same substrates using microfabrication techniques followed by an electrochemical etch based on a random micro-crack pattern observed in lower doped substrates which yielded faster propagating composites. These organized multiscale composites exhibited flame propagation speeds up to 500 m s⁻¹ indicating that reaction propagation can be controlled by structural modifications. (paper)