A Solvent-Free Coarse Grain Model for Crystalline and Amorphous Cellulose Fibrils

Area of Science:

• Biomass Science
• Computational Chemistry
• Materials Science

Background:

• Understanding cellulose structure and dynamics is crucial for developing cellulosic biofuels.
• Bridging length and time scales in simulations is essential for accurate biomass modeling.

Purpose of the Study:

• To develop a coarse-grained (CG) model for molecular dynamics (MD) simulations of cellulose.
• To enable simulations of cellulose structure and dynamics across extended length and time scales.

Main Methods:

• Developed a single bead per monomer CG model using distribution functions from atomistic MD simulations.
• Validated the model against crystalline cellulose structures, achieving stability over 1 μs without constraints.
• Extended the CG model to amorphous cellulose by targeting atomistic simulations of individual cellulose chains.

Main Results:

• The CG model accurately reproduces structural features of crystalline cellulose.
• The CG crystalline fibril remained stable over extended simulation times (>1 μs).
• Developed CG force fields capable of generating fibril structures with varying degrees of crystallinity.

Conclusions:

• The developed CG model offers an accurate, constraint-free method for simulating cellulose with diverse crystallinity.
• This approach is suitable for integration into large-scale models of lignocellulosic biomass.
• Facilitates advancements in cellulosic biofuel research through improved biomass simulation capabilities.