Figure : Quantifying average contact between cell wall components at different water weights (A, B) Atomistic models illustrating low and high moisture content, 5% and 30% water weights respectively in secondary cell wall in plants. In this figure, the cellulose microfibril is represented in blue, hemicellulose in green and lignin in orange. To maintain the same aspect ratio for the systems represented in panels (A) and (B), panel A is zoomed in further due to the smaller dehydrated system. The water is represented by red (oxygen atom) and white (two hydrogen atoms). (C) The average number of contacts between individual cell wall components -cellulose, hemicellulose, and lignin. The average number of contacts reduces as the moisture level increases, as water molecules diffuse in between the spaces impeding interaction between individual components. Figures 6A and 6B represent a molecular system of the plant secondary cell wall at low and high moisture content, 5 and 30 water weight percent respectively. Even after extensive equilibration under constant pressure conditions, we see that there may be large voids in between individual cell wall components. This is particularly true for models with lower water content, as water can more readily fill in gaps within the cell wall structure for hydrated cell walls. As a consequence, close contacts between different cell wall polymers goes down with increasing hydration (Figure ). By hydrating the system and removing interpolymer contacts, water acts as a lubricant to polymer motion within the cell wall. Fundamentally, the reduction in contacts demonstrated by Figure drives the increase in biopolymer motion first characterized in Figure . Figure also demonstrates why cellulose-hemicellulose and especially cellulose-lignin interactions have been historically so difficult to quantify, since there are just many more hemicellulose-lignin interactions, even in the absence of covalent linkages between the polymers. and Cu 2+ (orange) and snap shots of their interactions with the carboxylate functional group in hemicellulose shown in sticks with gray, red and white colors representing the carbon, oxygen, and hydrogen atoms respectively. Ion interaction reduces with increase in moisture content. Interaction between ions and hemicellulose are always higher compared to the interaction with either lignin or cellulose. Cations have a strong affinity towards hemicellulose, as it interacts strongly with the carboxylate group in hemicellulose. As the zoom levels while rendering the molecular structures were not the same, K + cation appears bigger than Na + and Cu 2+ cations.