Spatial and temporal control of on-demand propane–air flame ignition by active photothermal effect of aluminum nanoenergetics

Active photothermal effects of aluminum nanoenergetics are demonstrated to control spatially and temporally the ignition of propane/air flames. High-speed chemiluminescence images of hydroxyl (OH*) and methylidyne (CH*) radicals and aluminum oxide (AlO) are employed to confirm the local flame ignition and propagation by activation of the nanoenergetics through the use of a single exposure from a xenon flash lamp. The photothermal effects of the nanoenergetics can efficiently activate the localized exothermal aluminum oxidation reactions, leading to sequential flame ignition. Most of the energy required for ignition is provided by the oxidation reaction of the aluminum nanoparticles such that the photothermal MIE (Minimum Ignition Energy) is at least 67 times less than that from regular spark ignition.