Dynamical Water Ingress and Dissolution at the Amorphous-Crystalline Cellulose Interface.

Area of Science:

• Materials Science
• Physical Chemistry
• Polymer Science

Background:

• Cellulose's industrial potential is limited by moisture-induced mechanical property degradation.
• Current models predict equilibrium moisture content but lack atomic-scale dynamics of water interaction.
• Understanding water ingress dynamics is crucial for improving cellulose-based materials.

Purpose of the Study:

• To investigate the atomic-scale dynamics of water ingress and cellulose dissolution at the cellulose-water interface.
• To elucidate the influence of temperature and amorphous region chain length on these processes.
• To propose a mechanism explaining the initial stages of water-cellulose interaction.

Main Methods:

• Nonequilibrium molecular dynamics (MD) simulations were employed.
• The simulations focused on the interface between cellulose and water.
• Key parameters investigated included temperature and cellulose chain length.

Main Results:

• Water ingress and cellulose dissolution occur simultaneously at the interface.
• Higher temperatures promote greater mass exchange between water and cellulose.
• Shorter cellulose chains in the amorphous region detach more readily.
• A cooperative mechanism involving hydrogen bonding and chain intertwining governs the process.

Conclusions:

• The study provides a dynamical, atomic-scale view of water-cellulose interaction.
• Findings highlight the roles of temperature and chain length in moisture uptake and dissolution.
• This research lays the groundwork for functionalizing cellulose to enhance its moisture resistance and mechanical stability in applications.
• The proposed cooperative mechanism offers insights into mitigating degradation in nanocellulose materials.