Water Droplet Absorption into Cellulose-based Fabric: A Molecular Viewpoint

In this paper, we present the mechanisms of water droplet absorption into the cellulose-based fabric from a molecular viewpoint. A 5x5x5-unit-cells of cellulose I model and a water molecule model have been developed to represent fabric and water droplet. The climbing-image nudged elastic band method was used to find the minimum energy path and the energy barrier of a water molecule when absorbed into three different cellulose surfaces, i.e. [100], [010], and [001] surfaces. The [010] has the lowest calculated energy barrier compared to the other surfaces, thus it is the easiest surface to be penetrated by water molecules. The other surfaces have larger energy barrier values due to the temporary
binding of an oxygen atom of the water molecule on cellulose molecules when the water molecule penetrates the surface.
For all surfaces, there is not any chemical reaction taking place when the water molecule is adsorbed on the surface or when it is absorbed in the subsurface. Thus, the absorption processes observed in this study is physical absorption.