Interfacial structure and chain anisotropy in PVC/SiO2nanocomposites: a layer-resolved static analysis by molecular...

Area of Science:

• Materials Science
• Polymer Science
• Computational Chemistry

Background:

• The interphase between polymers and nanofillers dictates nanocomposite properties.
• Characterizing this interphase at a molecular level is challenging.
• Existing methods lack systematic, physically meaningful descriptions.

Purpose of the Study:

• To investigate the interfacial structuring of amorphous PVC near a SiO2 surface.
• To develop and compare methods for defining and analyzing polymer interphases.
• To establish a multiscale description of polymer-nanofiller interactions.

Main Methods:

• All-atom molecular dynamics simulations of PVC confined by SiO2.
• Development and comparison of three chain-based layer-assignment schemes.
• Analysis using correlation functions, structure factors, and gyration tensor.

Main Results:

• Pronounced layering and anisotropic organization normal to the interface were observed.
• Interfacial polymer chains showed increased shape anisotropy and surface-parallel alignment.
• A contact-aware model provided the most consistent description of interfacial structure.

Conclusions:

• Explicitly accounting for polymer-surface contacts is crucial for defining interphases.
• The study proposes a transferable framework for characterizing polymer interphases in nanocomposites.
• This work links local chemistry to mesoscopic structure and dynamics.