Gallium-based liquid metal display can be written on and erased with voltage

Advances in the field of soft robotics and flexible electronics have placed a renewed need for visual interfaces that can bend, stretch, and deform alongside these devices. Gallium-based liquid metal has shown promise for soft optical interfaces, but current approaches often rely on heterogeneous materials that add complexity and can compromise the material’s intrinsic fluidity.

Cheng et al. have developed a programmable, pixel-addressable liquid metal display and interactive paper form. Using a localized anodic oxidation reaction of liquid metals in acidic solution, the surface can rapidly and reversibly transition between reflective silver to high-contrast matte black on a light-trapping oxide film.

“Our work demonstrates that electrochemical surface modification is a powerful tool for manipulating the optical properties of liquid metal,” said author Jing Liu. “By providing a low power, soft matter-based display strategy, we offer a novel pathway for developing dynamic visual interfaces that can seamlessly integrate with flexible electronics.”

The film acts as a highly effective light trap, scattering and absorbing incident light to turn the reflective silver surface into a matte black state. Once voltage is removed, the film spontaneously dissolves in the acid, erasing the black pattern and restoring the metallic luster.

“The most surprising part of our work was the initial discovery itself, which happened quite serendipitously,” said Liu. “We observed that under specific acidic conditions, the liquid metal surface could instantly transform into a deep, matte black state upon applying a voltage, a phenomenon that is not commonly seen in other electrolytes.”

The group next looks to expand the device’s color palette, as well as improving resolution and scalability into high-density, large-area flexible screens that could one day be used in wearable devices.

Source: “Liquid metal display and Quasi-e-paper,” by Cai Cheng, Yibing Ma, Nan Li, Yiyue Tao, and Jing Liu, Applied Physics Letters (2026). The article can be accessed at https://doi.org/10.1063/5.0314328 .