Tunable thermal conductivity of π-conjugated two-dimensional polymers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Polymer Chemistry

Background:

• Two-dimensional (2D) polymers are emerging as versatile organic analogues to graphene.
• They offer superior tunability in structure, topology, and physical properties compared to graphene.
• Understanding the thermal transport properties of 2D polymers is critical for their technological applications but remains under-explored.

Purpose of the Study:

• To investigate the in-plane thermal conductivity of porous, π-conjugated 2D polymers.
• To elucidate the relationship between structural characteristics (porosity, orientation) and thermal transport.
• To challenge the conventional understanding of π-conjugation's effect on thermal conductivity.

Main Methods:

• Utilized equilibrium molecular dynamics simulations.
• Analyzed the in-plane thermal conductivity of porous graphene-like 2D polymers composed of π-conjugated phenyl rings.
• Investigated phonon dispersion to understand underlying thermal transport mechanisms.

Main Results:

• Demonstrated that π-conjugated 2D polymers can exhibit either high or low thermal conductivity.
• Showcased that thermal conductivity is highly dependent on the material's porosity and structural orientation.
• Observed a variance of up to two orders of magnitude in thermal conductivity by altering porosity.

Conclusions:

• The thermal conductivity of π-conjugated 2D polymers is not solely dictated by π-conjugation.
• Porosity and structural arrangement are key factors in determining thermal transport properties.
• Significant opportunities exist to engineer 2D polymers with tailored thermal conductivity for various applications.