Molecular Insights into Miscibility and Mechanical Modulation in PHBV/Chitosan Blends via Atomistic Simulations

Area of Science:

• Polymer Science
• Materials Science
• Computational Chemistry

Background:

• Chitosan (CS) is a versatile biopolymer limited by its rigidity.
• Polymeric blending with bio-based materials like PHBV is underexplored at the molecular level.
• Understanding PHBV's role in CS blends is crucial for material property modulation.

Purpose of the Study:

• To investigate the miscibility and mechanical modulation mechanisms in PHBV/CS blends using atomistic molecular dynamics simulations.
• To quantify molecular-level interactions and understand how polymer stiffness influences blend properties.
• To provide mechanistic guidance for designing biodegradable and mechanically adaptable polymer materials.

Main Methods:

• Atomistic molecular dynamics (MD) simulations.
• Calculation of Flory-Huggins interaction parameter for miscibility assessment.
• Steered MD simulations to analyze mechanical properties and chain dynamics.

Main Results:

• PHBV/CS blends exhibit favorable miscibility across various compositions and temperatures.
• Chitosan exhibits higher backbone stiffness and torsional resistance than PHBV.
• PHBV incorporation enhances CS chain mobility and ductility, with effects persisting in phase-separated morphologies.

Conclusions:

• Differences in polymer stiffness and conformational flexibility govern mechanical modulation in PHBV/CS blends.
• PHBV acts as an effective modifier, enhancing the processability and mechanical adaptability of CS.
• Findings support the development of novel, fully biodegradable, and mechanically tunable polymer materials.