Enhanced Electrocaloric Effect of PVDF-based Polymer Composite with Surface Modified AlN

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Relaxor ferroelectric polymers like P(VDF-TrFE-CTFE) show promise for electrocaloric effect (ECE) cooling but suffer from low thermal conductivity.
• Poor heat transfer limits the practical application of these polymers in cooling devices.

Purpose of the Study:

• To enhance the thermal conductivity and ECE of P(VDF-TrFE-CTFE) by incorporating aluminum nitride (AlN) nanoparticles.
• To address the reduced breakdown electric field caused by weak AlN-polymer interfaces through surface modification.
• To investigate the influence of nanoparticle size and interface effects on the ECE.

Main Methods:

• Surface modification of AlN nanoparticles to improve interfacial bonding with the P(VDF-TrFE-CTFE) matrix.
• Fabrication of composite films with varying AlN nanoparticle sizes.
• Characterization of breakdown electric field, ECE, and thermal conductivity of the composite films.

Main Results:

• Surface modification of AlN nanoparticles maintained a high breakdown electric field (~240 MV/m) in the composite films.
• The ECE and thermal conductivity of the composites were improved by 44% and 55%, respectively.
• A decrease in ECE was observed with increasing AlN nanoparticle size, highlighting the importance of the interface area.

Conclusions:

• Surface-modified AlN nanoparticles effectively enhance the ECE and thermal conductivity of ferroelectric polymer composites.
• The interfacial effect, ferroelectric-paraelectric phase transition, and Joule heating are key factors influencing the ECE in these composites.
• Optimizing the interface area is crucial for maximizing the electrocaloric cooling performance of nanoparticle-polymer composites.