# A Study of the Effect of Aniline Curing Agent Bridge Bonding Groups on Charge Injection at the Copper/Epoxy Interface

## TL;DR

This study explores how different aniline curing agents affect charge injection at copper/epoxy interfaces in high-voltage equipment.

## Contribution

The paper introduces new insights into how molecular structures of curing agents influence charge injection barriers at metal/epoxy interfaces.

## Key findings

- Molecular structures with -C2F6 bonds show higher injection barriers than those with -CH2.
- DDM reduces injection barriers due to low electronegativity and compact structure.
- 6FDAM increases barriers because of its strong electronegative nature.

## Abstract

Comprehending charge injection at the metal/epoxy interface is essential for designing and applying high-voltage electrical equipment. This study investigates surface charge accumulation in insulators used in high-voltage direct current (HVDC) gas-insulated switchgear (GIS), with a specific focus on the charge injection behavior at the metal/epoxy interface employing first-principles calculations. In this paper, two amine curing agents were selected to construct interface models of a Cu(111) slab and epoxy resin, with repeating fragments representing the crosslinked structure of the resin. Key parameters, including injection barriers, charge transfer, and vacuum energy level shifts (Δ), were evaluated. Notably, molecular structures containing -C2F6 bonds exhibited higher electron and hole injection barriers compared to those with -CH2. Specifically, DDM induces reduced interfacial charge injection barriers and enhanced charge transport capabilities attributed to its low electronegativity and compact spatial configuration, whereas 6FDAM yields elevated barrier heights stemming from its strong electronegative character. The reliability of these findings was further validated through macroscopic charge injection experiments. The above study holds certain referential value for the development and application of high-voltage DC GIS equipment.