Flexible multi-walled carbon nanotubes/polydimethylsiloxane membranous composites toward high-permittivity performance

As reported, flexible composites with high-permittivity performance have played a significance role in thin-film capacitors, stretchable electronic devices, etc. However, the flexibility of traditional high-permittivity composites with metal particles or conductive polymers was damaged near percolation threshold. In this work, an in situ polymerization process was used to prepare the flexible percolating multi-walled carbon nanotubes/polydimethylsiloxane (MWCNTs/PDMS) membranes. Meanwhile, the high-permittivity performance w as observed when the MWCNTs content was near but not exceeded the percolation threshold, attributing to the Maxwell-Wagner-Sillars effect. As MWCNTs content increased, the conduction mechanism of the MWCNTs/PDMS composites was changed from the hopping conduction to metal-like conduction, the conductivity values were enhanced as well, and thus, the main dielectric loss resulted from the ohmic dissipation. Furthermore, the tensile strength and elongation results demonstrated that the membranes were flexible and had good mechanical properties. This work not only revealed the mechanism of high permittivity in percolating composites but also promoted the applications of flexible high-permittivity membranes in capacitors, electromagnetic interference shielding, microwave absorption, and so on.