High thermal conductivity in electrostatically engineered amorphous polymers.

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• High thermal conductivity is crucial for polymer applications like LED packaging, requiring efficient heat dissipation.
• Bulk polymers typically exhibit low thermal conductivity (0.1-0.4 W m⁻¹ K⁻¹) due to coiled and entangled chain structures.

Purpose of the Study:

• To investigate the effect of polymer chain extension and stiffening on thermal conductivity.
• To explore molecular engineering strategies for enhancing thermal conductivity in amorphous polymers.

Main Methods:

• Systematic ionization of polyacrylic acid (PAA), a weak anionic polyelectrolyte.
• Fabrication of spin-cast amorphous films from ionized PAA.
• Measurement of cross-plane thermal conductivity of the films.

Main Results:

• Ionization of PAA led to extended and stiffened polymer chains with improved packing.
• Cross-plane thermal conductivity increased with the degree of PAA ionization.
• Achieved thermal conductivity reached ~1.2 W m⁻¹ K⁻¹, significantly higher than typical amorphous polymers.

Conclusions:

• Systematic ionization of PAA is an effective strategy to enhance thermal conductivity in amorphous polymers.
• The enhanced thermal conductivity approaches that of glass, indicating potential for high-performance applications.
• This study introduces a novel molecular engineering pathway for developing thermally conductive amorphous polymers.