# Polyimide-Based Nanocomposites with Ultra-High Dielectric Breakdown Strength: A Review and New Record

## TL;DR

This paper introduces a new method to significantly enhance the electrical insulation properties of polyimide-based nanocomposites using silica nanoparticles.

## Contribution

The novel contribution is achieving an ultra-high dielectric breakdown strength of ~1000 V/μm in polyimide-based nanocomposites through surface chemistry optimization.

## Key findings

- APTES-functionalized SiO2 nanoparticles improve dispersion and electrical properties of polyimide films.
- The nanocomposite shows a 68% enhancement in dielectric breakdown strength compared to pure polyimide.
- Lower permittivity, dielectric loss, and conductivity are achieved due to restricted dipolar motion and charge trapping.

## Abstract

A novel state-of-the-art record in the field of dielectric
breakdown
strength enhancement of polyimide-based nanocomposites is reported
in this work. This achievement has been obtained through accurate
optimization of the surface chemistry of silica (SiO2)
nanoparticles. An efficient surface functionalization using 3-aminopropyltriethoxysilane
(APTES) enabled the successful grafting of a single-layer ligand coverage
onto SiO2 and to reach an optimal colloidal stability,
promoting their homogeneous dispersion within the PI matrix. APTES-functionalized
PI/SiO2 nanocomposite films exhibit significant improvements
of the electrical insulation properties with lower permittivity, dielectric
loss, and conductivity under high electric field, all related to more
efficient dipolar motion restrictions and charge trapping effects.
This study demonstrates for the very first time the path to design
revolutionary ultrahigh breakdown field strength properties in a polyimide-based
nanocomposite with EBD ∼ 1000 V/μm and an
enhancement factor ηE ∼68% compared to pure
PI. Our results present a methodology for significantly advancing
the state-of-the-art, enabling polyimide-based nanocomposite films
to unlock future high-voltage applications, such as integrated insulation
and capacitive energy storage.