Ultralight and Flexible MWNTs/Polyimide Hybrid Aerogels for Elastic Conductors

Aerogels have showed tremendous potential applications because of its unique and outstanding properties. Herein, a novel two-step approach to form self-assembly nanocomposite aerogels driven by the strong interactions between water-soluble polyimide (PI) precursor polyamic acid salt (PAAs) and hydroxyl multiwalled carbon nanotubes (MWNTs-OH) is reported. The PI therein constitutes the framework of the nanocomposite and raises the strength of the cell walls, which endows aerogels with superelasticity and robustness. The MWNTs-OH is distributed uniformly into water via physical ultrasonic method followed by blending with PAA molecular. During the imidization process, electrically insulating polyamic acid (PAA)/MWNTs-OH aerogels are converted to conductive PI/MWNTs-OH nanocomposite aerogels owning to the removal of their oxygenic functional groups of. OH functionalized MWNTs. Moreover, adding multi-walled carbon nanotube (MWNTs) contributes to the reduction of shrinkage notably, which can be evidenced by scanning electron microscopy measurement and density data. The nanocomposite aerogels display a high elastic modulus, high compressive stress, superior robustness, and high stress-sensitive electrical conductivity. Interestingly, the variation trend of the electric resistance with compressive strain (R/R-0-epsilon) plots is consistent with the compressive stress-strain (sigma-epsilon) curves, which can be explained by the interface contact spots theory. And this finding could facilitate the development of polymer-based nanocomposite aerogels as elastic conductors for various applications.