Shapeshifting Liquid Metal Droplets for Soft Fluidic Machines

Abstract

Studying droplet dynamics is crucial for microfluidics, materials science and soft robotics. Electric and magnetic fields enable precise droplet handling for drug delivery and diagnostics, but high-energy inputs trigger droplet instabilities and explosive breakup. Here these materials instabilities are leveraged for high energy transduction in liquid metal droplets with high surface tension and conductivity. Liquid metal shapeshifting (LMSS) is introduced, a method for fluidic power generation that uses Lorentz forces and surface tension. Demonstrated in a low voltage (mean≤0.1V), soft, bidirectional pump, it features a simple design with two electrodes, one liquid metal drop, and a small magnet, which can be driven directly from an AAA battery, outperforming previous pumps. Demonstrating versatility, this shapeshifting approach is applied to create an active wearable photoprotective skin, soft robotic actuators, and adaptive color-changing units for clothing, establishing a range of material-focused applications. The liquid metal shapeshifting system represents a transformative material platform for compact, integrated fluidic power supplies and its potential spans applications across lab-on-a-chip devices, micro/macro robotics, adaptive materials, and wearable technologies, positioning it as a foundational technology for the next generation of multifunctional, fluidic-driven soft machines.