Sorption Hysteresis Modeling: a New Step toward the Understanding of Cell Wall Architecture

我们的目标是通过研究滞后现象来阐明纳米级的木材细胞壁结构。解释吸水过程中的滞后现象是生物聚合物，尤其是木材科学中一个长期存在的问题。最近的研究对经典理论用可及羟基解释滞后现象的能力提出了许多质疑。受新兴的纳米多孔材料和吸附科学的启发，以及我们对磁滞模式的初步研究，我们认为磁滞是由于吸附过程中水的相变(毛细管凝聚和细胞壁中的蒸发)中存在亚稳态造成的。由于相变受细胞壁孔尺寸的影响很大，通过物理模拟或模拟滞后现象，我们可以揭示不同水分含量下细胞壁孔尺寸的分布。

We aim to elucidate the nanoscale wood cell-wall architecture by studying the hysteresis phenomenon. Explaining the hysteresis phenomenon in water sorption is a long-standing problem in biopolymer and in particular, wood science. Recent studies cast a lot of doubts on ability of classical theories to explain hysteresis in terms of accessible hydroxyls. Inspired by emerging nanoporous materials and sorption science, and our preliminary investigation on hysteresis patterns, we propose that the hysteresis is caused by the existence of metastable states taking place in water phase transitions (capillary condensation and evaporation in cell-walls) during the sorption process. Because the phase transition is highly affected by cell-wall pore sizes, by physically modeling or simulating hysteresis, we may reveal the cell-wall pore size distribution under different moisture contents.