Researchers at Cornell University have developed a chip that produces tiny hydrogen bubbles whenever they are needed. Electricity splits water to create the gas. The team can adjust the bubbles’ size, number and position in real time, controlling individual bubbles or groups. The system could eventually help deliver medicine precisely to a particular place in the body.
The chip uses nine small electrodes, which provide electrical control. After creating the bubbles, the researchers apply ultrasound, a type of sound wave. This makes the bubbles vibrate and move the surrounding liquid. For strong movement, the sound frequency must match the bubble’s resonant frequency, which depends on its size. Applying electricity for longer makes a bubble grow larger.
Experiments showed that changing the bubbles’ sizes and positions changes the direction of liquid flow. Bubbles of equal size can work together to produce balanced flows, while the largest bubble determines the direction when sizes differ. Arranging five bubbles in an L-shape also allowed the team to guide liquid along a curve. These controls could support devices with adjustable paths for tiny amounts of liquid.
