Unveiling moisture transport mechanisms in cellulosic materials: Vapor vs. bound water - Archive ouverte HAL
Article Dans Une Revue PNAS Nexus Année : 2024

Unveiling moisture transport mechanisms in cellulosic materials: Vapor vs. bound water

Yuliang Zou
Laurent Brochard
Philippe Coussot

Résumé

Abstract Natural textiles, hair, paper, wool, or bio-based walls possess the remarkable ability to store humidity from sweat or the environment through “bound water” absorption within nanopores, constituting up to 30% of their dry mass. The knowledge of the induced water transfers is pivotal for advancing industrial processes and sustainable practices in various fields such as wood drying, paper production and use, moisture transfers in clothes or hair, humidity regulation of bio-based construction materials, etc. However, the transport and storage mechanisms of this moisture remain poorly understood, with modeling often relying on an assumption of dominant vapor transport with an unknown diffusion coefficient. Our research addresses this knowledge gap, demonstrating the pivotal role of bound water transport within interconnected fiber networks. Notably, at low porosity, bound water diffusion supersedes vapor diffusion. By isolating diffusion processes and deriving diffusion coefficients through rigorous experimentation, we establish a comprehensive model for moisture transfer. Strikingly, our model accurately predicts the evolution of bound water's spatial distribution over time across varying porosities, as verified through Magnetic Resonance Imaging (MRI). Showing that bound water transport can be dominant over vapor transport, this work offers a change of paradigm and unprecedented control over humidity-related processes.

Dates et versions

hal-04357225 , version 1 (21-12-2023)

Identifiants

Citer

Yuliang Zou, Benjamin Maillet, Laurent Brochard, Philippe Coussot. Unveiling moisture transport mechanisms in cellulosic materials: Vapor vs. bound water. PNAS Nexus, 2024, 3 (1), ⟨10.1093/pnasnexus/pgad450⟩. ⟨hal-04357225⟩
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