MARTINI Coarse-Grained Force Field for Thermoplastic Starch Nanocomposites

Area of Science:

• Materials Science
• Computational Chemistry
• Polymer Science

Background:

• Thermoplastic starch (TPS) is a promising biodegradable film-forming material for packaging.
• Incorporating fillers like tetramethylammonium-montmorillonite (TMA-MMT) clay enhances TPS properties.
• Accurate simulation models are crucial for understanding and optimizing TPS-TMA-MMT composites.

Purpose of the Study:

• To develop and validate a coarse-grained (CG) force field for thermoplastic starch (TPS) and TPS-TMA-MMT composites.
• To predict macroscopic and microscopic properties of TPS and its composites using molecular simulations.
• To establish a robust CG model for future simulations of advanced packaging materials.

Main Methods:

• All-atom (AA) simulations were used to determine macroscopic and microscopic properties of TPS and TPS-TMA-MMT.
• A MARTINI-2 coarse-grained (CG) force field was parameterized using AA simulation data.
• The CG model was optimized and validated against various structural, thermodynamic, and dynamic properties.

Main Results:

• The developed MARTINI-2 CG model accurately predicted key properties of TPS melt and TPS-TMA-MMT composites.
• Simulations revealed distinct conformational and dynamic behaviors influenced by polymer-surface and polymer-plasticizer interactions.
• The model successfully captured chain compaction and altered interactions near the clay surface.

Conclusions:

• The developed CG force field is robust and reliable for simulating TPS and TPS-TMA-MMT systems.
• This model provides a powerful tool for designing and optimizing biodegradable packaging materials.
• The study highlights the importance of accurate force fields in predicting composite material behavior.