Particle Diffusion Process with Artificial Control: Diffusion Metamaterials

Diffusion acts as a fundamental process for both energy and mass movement, showcasing dynamics that differs from wave propagation. The emergence of metamaterials provides a robust platform for custom manipulations of mass diffusion, drawing on principles like transformation theory and scattering-cancellation theory. Such manipulations have set the stage for novel findings and pioneering applications. This chapter delves into a thorough analysis of the recent progress in diffusion metamaterials. Earlier studies are methodically categorized based on diffusion models, delving deeply into the related theories, applications, finite-element simulations, and experimental approaches of different mechanisms. The chapter wraps up with a scrutiny of the inherent challenges tied to the theoretical underpinnings and architectural design of diffusion metamaterials. Some of these challenges are seen as potentially mitigated by upcoming approaches, such as pseudo-conformal mapping and machine-learning methodologies.