Enhancing Polymer Composite Thermal Conductivity by Liquid Metal and Carbon Fiber Dual Fillers

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Polymers like poly(vinylidene fluoride) (PVDF) are widely used but have poor thermal conductivity.
• Enhancing polymer thermal conductivity is crucial for applications like thermal management.

Purpose of the Study:

• To develop thermally conductive PVDF composites using dual fillers: eutectic gallium-indium (EGaIn) liquid metals (LMs) and carbon fibers (CFs).
• To investigate the impact of LMs and CFs on the thermal, mechanical, and structural properties of PVDF composites.

Main Methods:

• Preparation of PVDF composites with varying concentrations of LMs and CFs.
• Characterization using thermal conductivity measurements, morphology analysis (SEM), crystallinity assessment (XRD), and mechanical testing (tensile strength).

Main Results:

• A maximum thermal conductivity of 0.40 W/(m·K) was achieved (154% increase over pure PVDF) with 5 wt% LMs and 1 wt% CF.
• CFs improved LM dispersion, forming conductive pathways and enhancing thermal conductivity.
• Mechanical testing revealed that CFs compensated for LM-induced strength reduction, resulting in tensile strength comparable to pure PVDF.
• Structural analysis confirmed the PVDF matrix's crystalline and chemical integrity was preserved.

Conclusions:

• PVDF/LM/CF composites demonstrate a synergistic enhancement of thermal conductivity and mechanical strength.
• These composites are promising for thermal management applications.
• The study offers insights into designing high-performance, dual-functionality polymer composites.