Humidity-stable submicron magnesium oxide particles for high-performance thermally conductive composites

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Chemistry

Background:

• Spherical magnesium oxide (MgO) microparticles offer good dispersibility but limited thermal conductivity enhancement in polymer matrices.
• Submicron MgO particles improve thermal conductivity by increasing contact points, but conventional methods yield moisture-reactive particles.
• Existing fabrication methods struggle to produce submicron MgO particles with sufficient humidity resistance for practical applications.

Purpose of the Study:

• To develop a novel bottom-up synthesis approach for submicron MgO particles.
• To achieve superior humidity resistance and enhanced thermal conductivity in the synthesized MgO particles.
• To evaluate the performance of these particles as fillers in thermally conductive polymer composites.

Main Methods:

• Synthesized a polymeric precursor via polymerization of citric acid and ethylene glycol.
• Utilized spray drying to form precursor particles.
• Employed a two-step heat treatment involving oxidation and liquid-phase sintering to yield dense, submicron MgO particles.

Main Results:

• The synthesized submicron MgO particles demonstrated excellent humidity resistance, with only a 1.03% weight variation.
• Incorporation of these particles into a polydimethylsiloxane matrix significantly enhanced thermal conductivity to 6.0 W m⁻¹ K⁻¹ at 80 vol% filler content.
• The composite's thermal conductivity (6.0 W m⁻¹ K⁻¹) was substantially higher than that of composites without submicron MgO (4.4 W m⁻¹ K⁻¹).

Conclusions:

• A novel, humidity-resistant submicron MgO particle synthesis method was successfully established.
• These particles significantly boost the thermal conductivity and provide electrical insulation for polymer composites.
• The developed MgO particles are promising for advanced heat management in next-generation electronic devices.