Hierarchical Traps Modulated Charge Transport of Dielectric Polymers toward Enhanced Breakdown Performance

Area of Science:

• Materials Science
• Polymer Physics
• Dielectric Engineering

Background:

• Charge carrier dynamics (trapping, detrapping, transport) are critical for dielectric polymer performance in high-voltage equipment.
• Polymer structural inhomogeneities, specifically microphase crystallization, influence charge dynamics but remain poorly understood.
• Designing high-performance dielectric polymers is hindered by the unresolved contribution of these inhomogeneities to charge dynamics.

Purpose of the Study:

• To investigate the microscopic origins of intramolecular trap distributions generated by structural inhomogeneities in dielectric polymers.
• To elucidate how these trap distributions modulate charge transport mechanisms.
• To correlate specific polymer structures with enhanced electrical performance.

Main Methods:

• Synthesis of dielectric polymers with customized gradient branched structures.
• Analysis of intramolecular trap distributions and their hierarchical arrangement.
• Investigation of charge carrier transport mechanisms influenced by these trap structures.
• Evaluation of dielectric breakdown performance.

Main Results:

• Customized gradient branched structures induce rich deep traps, forming ordered trap blocks with hierarchical energy levels.
• Trap energy and density decrease hierarchically from the deepest block towards chain terminals.
• This hierarchical configuration promotes short-range charge transport, suppressing long-range hopping and energy accumulation.
• Achieved a 12.5% enhancement in breakdown performance (701.1 kV/mm) compared to random copolymers.

Conclusions:

• The study reveals a novel charge transport mechanism driven by hierarchical intramolecular trap distributions in dielectric polymers.
• Gradient branched structures offer a pathway to engineer trap distributions for improved electrical performance.
• The findings are expected to guide the development of next-generation dielectric polymers with tailored electrical properties for demanding applications.