Large Dielectric Constant Enhancement in MXene Percolative Polymer Composites

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Poly(vinylidene fluoride) (PVDF)-based composites are crucial for electronic applications.
• Enhancing dielectric properties of polymers remains a key challenge.
• Two-dimensional (2D) MXene nanosheets offer unique properties for composite materials.

Purpose of the Study:

• To investigate the dielectric properties of PVDF-based composites filled with 2D MXene nanosheets.
• To explore the potential of MXene as a filler for high-performance dielectric materials.
• To understand the mechanism behind the enhanced dielectric permittivity.

Main Methods:

• Fabrication of poly(vinylidene fluoride-trifluoro-ethylene-chlorofluoroehylene) (P[VDF-TrFE-CFE]) composites with varying loadings of 2D Ti₃C₂T_x MXene nanosheets.
• Characterization of dielectric permittivity and dielectric loss using impedance spectroscopy.
• Analysis of filler-matrix interactions and charge accumulation mechanisms.

Main Results:

• A dielectric permittivity as high as 10⁵ was achieved near the percolation limit (15.0 wt % MXene).
• The dielectric loss increased only ~5-fold (0.06 to 0.35) with up to 10 wt % MXene loading, while the dielectric constant increased 25-fold.
• The permittivity to loss factor ratio in MXene/P(VDF-TrFE-CFE) composites surpasses that of previously reported fillers.
• The dielectric enhancement effect was observed in other polymers loaded with MXene.

Conclusions:

• 2D MXene nanosheets significantly enhance the dielectric permittivity of PVDF-based composites.
• The enhanced dielectric properties are attributed to charge accumulation at MXene-polymer interfaces forming microscopic dipoles.
• MXene is a promising filler for developing high-performance dielectric materials for advanced applications.