Ultralight and Flexible MWNTs/Polyimide Hybrid Aerogels for Elastic Conductors

Abstract

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/R0–ε) plots is consistent with the compressive stress–strain (σ–ε) 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.

Flexible pressure sensors with high pressure sensitivity and low detection limit using a unique honeycomb-designed polyimide/reduced graphene oxide composite aerogel

“…indicating more superior elasticity and fatigue resistance compared with compressible carbon aerogels or sponges, 39,40 and porous composite aerogels or foams. [41][42][43][44][45] Besides, the stress-strain curves of the PI/rGO-5, PI/rGO-10, PI/rGO-15 aerogels at different strain rates (5-150 mm min À1 ) almost overlap, indicating that the composite aerogels can maintain excellent compression stability even under rapid deformation ( Fig. 3f and S7 †).…”

Sn‐Polyester/Polyimide Hybrid Flexible Free‐Standing Film as a Tunable Dielectric Material

“…Loss also increases by the incorporation of the Sn‐polyesters, mostly in the higher frequency regions. Lower loss is observed for the pDMTDMG hybrids (0.007–0.041) compared to pDMTGlu hybrids (0.009–0.058), which is much lower than any known hybrid system . Their trends in the κ and tan δ at 1 kHz in room temperature are shown in Figure C,D for all compositions.…”

“…Recently, polyimides (PIs) containing hybrid materials are of great interest and are receiving extensive consideration due to their improved morphological, thermal, and electrical properties . PI with a dianhydride, 3,3´,4,4´‐benzophenonetetracarboxylic dianhydride (BTDA), and an aliphatic diamine linker 1,6‐hexadiamine (HDA) was also synthesized by our team .…”

Fabrication and properties of anisotropic polyimide aerogels with aligned tube‐like pore structure

“…This indicated that the PI aerogel prepared by ice crystal‐induced self‐assembly still had excellent thermal stability. Due to the hydrolysis of PAA during the preparation of PAA powder from the purchased PAA solution, the molecular weight of PI would also decline. As a result, the initial decomposition temperature of PI aerogel prepared with 8 wt % PAA was 8 °C lower than that of PI film and 8 °C higher than that of PI aerogel prepared with 6 wt % PAA due to the lower water content and less hydrolysis of PAA.…”