Highly conductive multifunctional graphene polycarbonate nanocomposites.

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Bisphenol A polycarbonate (PC) is a versatile thermoplastic.
• Graphene offers exceptional electrical and mechanical properties.
• Developing advanced nanocomposites requires understanding filler dispersion and network formation.

Purpose of the Study:

• To investigate the electrical properties of graphene-bisphenol A polycarbonate nanocomposites.
• To compare the effectiveness of emulsion mixing and solution blending methods.
• To correlate microstructure with electrical conductivity and mechanical performance.

Main Methods:

• Preparation of graphene-PC nanocomposites using emulsion mixing and solution blending.
• Compression molding at 287 °C.
• Electrical conductivity measurements (dc and frequency-dependent).
• Dynamic mechanical analysis (DMA).
• Microstructural analysis using High-Resolution Transmission Electron Microscopy (HR-TEM) and Small-Angle Neutron Scattering (SANS).

Main Results:

• Electrical percolation thresholds of ~0.14 vol % (emulsion) and ~0.38 vol % (solution).
• Conductivities up to 0.512 S/cm for 2.2 vol % graphene nanocomposites (emulsion).
• Frequency-independent conductivity observed at higher graphene loadings.
• Increased dynamic tensile moduli with graphene content.
• Decreased glass transition temperatures with graphene (emulsion series).
• Microscopy confirmed graphene dispersion and connectivity correlating with conductivity.

Conclusions:

• Graphene's inherent conductivity, aspect ratio, and nanostructure assembly are key to high electrical properties.
• Emulsion mixing yields superior electrical performance compared to solution blending.
• Microstructural analysis provides insights into conductive pathways in graphene-PC nanocomposites.