The molecular system of the plant secondary cell wall 1 reused the earlier reported 30 % water weight (wt%) system from Sarkar et al. At this stage, the model was acetylated by chemically modifying exposed hydroxyl groups on hemicellulose and lignin polymers. Prior studies suggest that the dense packing of cellulose chains within a secondary cell wall precludes substantial acetylation. Using a custompatch and psfgen in Visual Molecular Dynamics (VMD), our acetylation procedure replaces water-exposed hydroxyl functional group with an acetyl functional group. The script first identifies the atom indexes for the hydroxyl functional group in lignin and hemicellulose, which are within 3, 6, or 12 Å distance from water. In addition, we have a fourth scenario, where all hydroxyl in lignin and hemicellulose are acetylated, corresponding to 18 % increase in dry weight. The precise WPG for each scenario, as well as the fraction of all total hydroxyl groups that are acetylated are reported in Table . The degrees of acetylation are quantified in terms of % dry weight gain, which has been derived using the Eq. 1.