Non-Fickian diffusion in biomaterials

[EN] The knowledge of water vapour diffusion in biomaterials is very important in several fields of application (drying, building materials, food packaging…). The process of vapour water transfer in biomaterials is usually described by Fick’s law of diffusion. Nevertheless, sometimes the experimental data of transient experiments in biosourced materials do not respect the standard Fickian model. The precise determination and formulation of this non-Fickian behaviour is therefore an important topic. This work presents a new methodology to quantify the non-Fickian diffusion. Based on memory functions and imbedded in a comprehensive heat and mass transfer computational model, the method is robust and prone to be applied to different biomaterials. Examples of application are proposed in the case of biofilms and lignocellulosic materials.