Particle Swarm Metamaterials for Information Display, Memory and Encryption

Metamaterials are emerging as an unconventional platform to perform computing abstractions in physical systems by processing environmental stimuli into information. While simple computation functions have been demonstrated in mechanical systems, they usually rely on compliant mechanisms to achieve predefined states, which impose inherent design restrictions that limit their miniaturization, deployment, reconfigurability, and functionality. Rather than relying on architected structure only, engineering intelligent functions through active matter design opens new opportunities for wide-spectrum programmability, reconfigurability, and miniaturization in metamaterials to perform advanced complex functions without compromising the device design space, thus bypassing state-of-the-art inherent limitations.
Here, we will describe a metamaterial system based on responsive magnetoactive Janus particle (MAJP) swarms with multiple programmable functions. MAJPs were designed and fabricated by scalable electrohydrodynamic (EHD) co-jetting with engineered functional compartments that provide tunable structure and properties that enable fast swarming response, remote actuation, and advanced functions in electronics-free configurations, which massively facilitate integration in soft and flexible devices. Leveraging the versatility of MAJPs and their tunable structure/properties, we designed and encoded swarming behavior and fully reversible switching mechanisms to enable programmable dynamic display, non-volatile and semi-volatile memory, Boolean logic, and information encryption functions in soft, wearable devices. MAJPs and their responsive behaviors open new functions for the design of multifunctional and reconfigurable display devices, and constitute a promising building block to develop the next generation of soft physical computing devices, with growing applications in security, defense, anti-counterfeiting, camouflage, soft robotics, and human-robot interaction.