As in prior simulations, we use the CHARMM36 force field for lignin and carbohydrates to describe the essential cell wall biopolymers lignin, hemicellulose and cellulose respectively. However, acetylated lignin and hemicellulose are not included in the above forcefield and hence additional parameters were required. We used the CHARMM general force field (CGenFF) to develop models for acetyl-patched monomers to fill in missing parameters identified by Force Field Toolkit (ffTK) plugin in VMD. These parameters are included within the data archive available in Zenodo (). Independent microsecond long equilibrium molecular dynamics (MD) simulations were performed for different acetylation degrees (0 -18 %), for monovalent (Na + ) and trivalent (Fe 3+ ) cation species. Prior to production simulation with the GPU-resident integrator in NAMD versions 3.0a9 through 3.0b6, 56 the systems were briefly minimized using NAMD 2.14 to arrive at a starting state for dynamics. Each system was simulated for 1000 ns to allow for internal diffusion and to evaluate structural rearrangements in the cell wall microenvironment. Following the conventions for the CHARMM36 force field, short range electrostatics and van der Waals terms were cutoff at 12 Å with a 10 Å switch and the TIP3 water model. Long range electrostatics was handled through the particle mesh Ewald method with a 1.2 Å grid spacing. Each integration timestep was set to 2 fs, with bond lengths to hydrogen restrained. A Langevin thermostat was used maintains a 300K temperature using a 5 ps -1 damping coefficient applied to all heavy atoms. Constant pressure was maintained at 1 atm via a semi-isotropic Langevin barostat, where the dimensions perpendicular to the cellulose fibril axis varied together.