Inelastic behaviour of cellulose microfibril networks

Area of Science:

• Materials Science
• Biomaterials Engineering
• Rheology

Background:

• Cellulose microfibrils (CMF) are versatile bio-nanomaterials with desirable properties.
• The non-linear mechanical behavior of CMF networks is complex and under-studied.
• Understanding CMF network mechanics is crucial for designing advanced bio-based materials.

Purpose of the Study:

• To systematically investigate the non-linear rheological behavior of cellulose microfibril networks.
• To explore the influence of controlled process conditions and inter-fibril interactions.
• To establish a foundation for modeling CMF network mechanics.

Main Methods:

• Utilized a model system of cellulose microfibrils dispersed in dimethyl sulfoxide.
• Minimized attractive van der Waals forces and network heterogeneity.
• Systematically applied varying shear stress and loading rates to rheologically characterize the networks.

Main Results:

• Observed a transition from elastic to plastic deformation with increasing shear stress, accompanied by softening.
• Demonstrated that network stiffness and plasticity are dependent on the loading rate.
• Confirmed that viscoelastic moduli are fully recovered upon cessation of shear.

Conclusions:

• Cellulose microfibril networks exhibit shear-induced softening and rate-dependent mechanical properties.
• The controlled system provides insights into the fundamental mechanics of CMF networks.
• These findings are essential for the rational design and application of novel cellulose-based materials.