Conventional wisdom holds that a microscopic bubble of gas, no matter how reactive its contents, makes for a stubborn explosive. That’s because explosive combustion sustains itself on recycled energy: Reacting molecules generate heat, which in turn incites more molecules to react, and so on. Due to its large surface-to-volume ratio, however, a microscopic bubble tends to lose heat to its surroundings so fast that the chain of reactions stops before it ever truly gets going.
Few people are more familiar with that problem than Vitaly Svetovoy, Miko Elwenspoek, and their colleagues at the University of Twente in the Netherlands. Looking to develop a novel type of fast and powerful electrochemical actuator, they fashioned an array of microelectrodes that, supplied with alternating voltage pulses, could extract micron-sized bubbles of hydrogen and oxygen from water. But their varied attempts to ignite the bubbles were to no avail.
On increasing the pulse frequency...
