Interfacial regions in spherical nanoparticle-doped glassy polymers: interfaces or interphases?

Whether an extra, subtle high-free-volume interphase in glassy polymers containing spherical nanoparticles really exists remains an open question, posing fundamental challenges for accurately predicting and intentionally tailoring the macroscopic transport behavior of these nanocomposites, which is crucial for a broad spectrum of industrial applications. Herein, we report new evidence supporting this controversial interphase by computational simulation and offer a generic framework for understanding how the interphase is shaped, based on a comparative strategy. This framework, validated by our previous experimental data, may provide guidance for rationally designing interfacial architectures in these nanocomposites that enable bottom-up tuning of their transport properties for specific applications.