Non-Fickian diffusion

Non-Fickian diffusion describes a process where particles spread through a material in a way that doesn't follow the typical, straightforward pattern predicted by Fick's laws. Instead of moving purely from areas of high to low concentration at a constant rate, their movement may be influenced by factors like the material’s structure, particle interactions, or other complex mechanisms. This results in a slower or more variable spread, often observed in dense or complex systems such as polymers or biological tissues, where the simple assumptions of Fickian diffusion don’t fully apply.