Digital Composite with Independently Programmable Mechanical Properties

Non-living materials typically exhibit fixed properties. The pre-set mechanical characteristics often compromise stability, performance, and efficiency, limiting the maximum potential of materials in varying conditions. Artificial materials that can actively change and adapt properties are highly desired. Here, we introduce a digital composite that comprises a grid of "voxels," each capable of individually transitioning between a soft, fluid state and a rigid, solid state. Each voxel is a chamber of liquid metal embedded within a silicone matrix, digitally controlled via local joule heating. This allows for real-time programming of the material's emergent mechanical properties based on collective voxel behavior. This system serves as a tangible simulation platform for experimentally investigating the mechanics of multi-material composite systems. Using this platform, we demonstrate the capability to program a variety of mechanical properties independently through statistical topological parameters. The resulting composites, which can be extended into 3D, can emulate a range of natural soft materials. The real-time programmability enables the material to produce desired stress-strain responses, exhibiting unconventional mechanical behaviors. The ability to digitally fine-tune the complex mechanics of materials introduces unprecedented flexibility in the microstructural design of materials for specific applications.