Interface Probing by Dielectric Frequency Dispersion in Carbon Nanocomposites

TL;DR

This paper demonstrates that high-frequency dielectric spectroscopy effectively probes static and dynamic interfacial properties in carbon nanotube/silicone rubber nanocomposites, revealing insights into interface reconstruction and meso-structural characteristics.

Contribution

First study to link dielectric frequency dispersion with interfacial and meso-structural features in carbon nanocomposites, enabling better interface understanding and material design.

Findings

Dielectric dispersion correlates with interfacial parameters.

Dielectric measurements reveal interface reconstruction.

Dielectric spectroscopy captures evolution of interfacial properties.

Abstract

Interfaces remain one of the major issues in limiting the understanding and designing polymer nanocomposites due to their complexity and pivotal role in determining the ultimate composites properties. In this study, we take multi-walled carbon nanotubes/silicone rubber nanocomposites as a representative example, and have for the first time studied the correlation between high-frequency dielectric dispersion and static/dynamic interfacial characteristics. We have found that the interface together with other meso-structural parameters (volume fraction, dispersion, agglomeration) play decisive role in formulating the dielectric patterns. The calculation of the relaxation times affords the relative importance of interfacial polarization to dipolar polarization in resultant dielectric relaxation. Dielectric measurements coupled with cyclic loading further reveals the remarkable capability of dielectric frequency dispersion in capturing the evolution of interfacial properties, such as a particular interface reconstruction process occurred to the surfactant-modified samples. All these results demonstrate that high-frequency dielectric spectroscopy is instrumental to probing both static and dynamic meso-structural characteristics, especially effective for the composites with relative weak interfaces which remains a mission impossible for many other techniques. The insights provided here based on the analyses of dielectric frequency dispersion will pave the way for optimized design and precise engineering of meso-structure in polymer nanocomposites.