The Electrical-Thermal Switching in Carbon Black-Polymer Composites as a Local Effect

TL;DR

This study uses atomic force microscopy to investigate the microscopic electrical-thermal switching mechanism in Carbon Black-Polymer composites, revealing that switching occurs at critical interparticle junctions influencing the macroscopic behavior.

Contribution

It provides the first microscopic insight into the local switching events, linking them to interparticle tunneling junctions and their dynamic behavior.

Findings

Switching occurs at critical interparticle tunneling junctions.

The macroscopic state results from fast switching and slow reconnection dynamics.

Atomic force microscopy reveals local switching mechanisms.

Abstract

Following the lack of microscopic information about the intriguing well-known electrical-thermal switching mechanism in Carbon Black-Polymer composites, we applied atomic force microscopy in order to reveal the local nature of the process and correlated it with the characteristics of the widely used commercial switches. We conclude that the switching events take place in critical interparticle tunneling junctions that carry most of the current. The macroscopic switched state is then a result of a dynamic-stationary state of fast switching and slow reconnection of the corresponding junctions.