Insights into interphase thickness characterization for graphene/epoxy nanocomposites: a molecular dynamics...

Area of Science:

• Materials Science
• Polymer Science
• Computational Chemistry

Background:

• Thermo-mechanical properties of nanocomposites are dictated by the interphase region.
• Characterizing this interphase, specifically its thickness, is crucial for material design.
• Graphene/epoxy nanocomposites are advanced materials with potential applications in various industries.

Purpose of the Study:

• To develop and present a novel methodology for systematically quantifying interphase thickness in graphene/epoxy nanocomposites.
• To investigate the influence of epoxy crosslinking density and the number of graphene layers on interphase thickness.
• To analyze the underlying mechanisms, including interaction energies and polymer dynamics, that govern interphase properties.

Main Methods:

• Molecular dynamics simulations were employed to model graphene/epoxy nanocomposites.
• A new method analyzing local mass density profiles using average accumulated mass density, accumulated standard deviation (ASD), and its first derivative was developed.
• Systematic analysis of interaction energies, polymer dynamics, component distribution, and polymer chain conformation was performed.

Main Results:

• The developed methodology effectively quantifies interphase thickness, overcoming the challenges posed by density profile oscillations.
• Epoxy crosslinking density was identified as the primary factor influencing interphase thickness, with higher crosslinking leading to thicker interphases.
• A secondary influence was observed from interaction energy, showing an inverse relationship with crosslinking density in this study.

Conclusions:

• The study provides a reliable method for interphase thickness detection in thermoset composites.
• Crosslinking density is the dominant parameter controlling interphase thickness in graphene/epoxy systems.
• Understanding interphase properties is key to optimizing the performance of advanced nanocomposites.