Multifunctional Bicontinuous Composite Foams with Ultralow Percolation Thresholds.

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Science

Background:

• Achieving ultralight weight and high mechanical strength in cellular materials remains a significant challenge.
• Developing multifunctional materials with tunable properties is crucial for advanced applications.

Purpose of the Study:

• To propose a skeleton-assisted self-assembly method for creating ultralight bicontinuous composite foams (BCCFs).
• To investigate the mechanical, electrical, microwave-absorbing, and oil-adsorbing properties of these novel BCCFs.

Main Methods:

• Utilizing polymer foam as a skeleton to support assembled graphene networks.
• Infiltrating the BCCFs with paraffin and poly(dimethylsiloxane) to enhance properties.
• Characterizing mechanical strength, electrical conductivity, microwave absorption, and oil adsorption capacity.

Main Results:

• BCCFs exhibited high tensile strength (∼80 kPa) and breakage elongation (>22.2%).
• Achieved a record low percolation threshold (0.006 vol %) and high electrical conductivity (0.81 S m^-1) at low graphene content (0.216 vol %).
• Demonstrated adjustable microwave-absorbing properties with a 9.0 GHz effective absorption bandwidth at 3.4 mg cm^-3 graphene loading, adjustable up to 13.6 GHz.
• Showcased efficient oil adsorption (>60 times own weight) at an extremely low graphene load (0.14 mg cm^-3).

Conclusions:

• The skeleton-assisted self-assembly method successfully produces ultralight, mechanically robust, and multifunctional BCCFs.
• These BCCFs offer tunable electrical, microwave-absorbing, and oil-adsorbing properties, indicating broad application potential.
• The facile fabrication process paves the way for practical, high-performance graphene-based foam applications.