Enhancing the OPLS-AA force field for cellulose Iβ: structural stability and surface functionalization capability...

Area of Science:

• Materials Science
• Computational Chemistry
• Biophysics

Background:

• Molecular dynamics (MD) simulations are crucial for understanding cellulose Iβ properties.
• Existing MD models struggle to accurately reproduce experimental structural data for cellulose Iβ.
• Limitations exist in modeling surface-functionalized cellulose, hindering application development.

Purpose of the Study:

• To enhance the OPLS-AA force field for stable cellulose Iβ crystalline integrity.
• To develop a robust model for simulating surface-functionalized cellulose Iβ.
• To improve the accuracy of MD simulations for cellulose Iβ.

Main Methods:

• Combined the CM5 charge model with the OPLS-AA force field for carbohydrates, creating the CM5-OPLS model.
• Evaluated the model's performance in retaining hydrogen bond populations and preserving conformations.
• Validated the model by comparing simulated unit cell parameters with experimental data.

Main Results:

• The CM5-OPLS model significantly improved stability compared to the original OPLS-AA.
• It retained high percentages of primary alcohol group conformations and hydrogen bond populations.
• Unit cell parameters were reproduced with <1.5% error, outperforming CHARMM36 and GLYCAM06.
• Accurate prediction of thermal and mechanical properties was achieved.
• Successful modeling of surface-functionalized cellulose Iβ was demonstrated.

Conclusions:

• The CM5-OPLS model offers a significant advancement for MD simulations of cellulose Iβ.
• It provides a reliable tool for studying both native and surface-functionalized cellulose Iβ.
• This improved model facilitates a deeper understanding and modification of cellulose for diverse applications.