Cetyltrimethylammonium bromide decorated MXene/polyimide nanocomposites with enhanced dielectric properties, thermostability, and moisture resistance

Abstract

Under extreme conditions, the polymer dielectric materials are expected to have good dielectric properties and heat resistance. Polyimide (PI) has high service temperature (>250°C) and low dielectric loss, but its low dielectric constant limits its further application. The addition of MXene can significantly improve the dielectric constant of PI, but the poor compatibility between MXene and weak polar matrix leads to Bénard‐Marangoni (BM) instability in the process of thermal imidization. This issue can be solved by the surface modification of MXene. Therefore, in this work, a new cetyltrimethylammonium bromide (CTAB) decorated MXene/PI nanocomposite film was prepared by in‐situ polymerization. With the addition of 7 wt% MXene@CTAB, the PI nanocomposite shows improved dielectric constant (k = 7.8 at 100 Hz), which is 2.4 times that of pure PI due to the formation of micro‐capacitors structure and Maxwell‐Wagner‐Sillars (MWS) interfacial polarization. Its dielectric loss keeps at an ultra‐low level (0.027 at 100 Hz) while that of 7 wt% MXene/PI nanocomposite is 3.027. It is owing that CTAB inhibits the agglomeration of MXene. In addition, MXene@CTAB/PI composites have excellent thermal stability, good hydrophobicity, and low water absorption. The above properties ensure MXene@CTAB/PI composites wide application in various extreme situations.

Construction of sandwich‐layered polyimide hybrid films containing double core–shell structured fillers for high energy storage density

“…The carboxyl group of PAA within 3200–2600 cm −1 disappears in these five groups, indicating that all of these PI‐based composites have been synthesized successfully after the thermal imidization of PAA. As depicted in the ATR‐FTIR spectra, the characteristic peaks at 1778 cm −1 (the asymmetric stretching vibration of CO in the imine ring), 1711 cm −1 (the symmetric stretching vibration of CO in the imine ring), 1376 cm −1 (the stretching vibration of CN in the imine ring), 1233 cm −1 (the stretching vibration of COC band), and 731 cm −1 (the bending vibration of CO in the imide ring) appear in all these films 42 . Meanwhile, all of the films contain the symmetric and asymmetric stretching vibration peaks at 1330, and 1140 cm −1 of SO 2 , which belong to PI matrices.…”

“…As depicted in the ATR-FTIR spectra, the characteristic peaks at 1778 cm À1 (the asymmetric stretching vibration of C O in the imine ring), 1711 cm À1 (the symmetric stretching vibration of C O in the imine ring), 1376 cm À1 (the stretching vibration of C N in the imine ring), 1233 cm À1 (the stretching vibration of C O C band), and 731 cm À1 (the bending vibration of C O in the imide ring) appear in all these films. 42 Meanwhile, all of the films contain the symmetric and asymmetric stretching vibration peaks at 1330, F I G U R E 2 SEM of (A) BaTiO 3 , (B) BaTiO 3 @MgO, and (C) BaTiO 3 @MgO@PDA. TEM images of (D) BaTiO 3 @MgO, (E) BaTiO 3 @MgO@PDA, and (F) EDS spectra of BaTiO 3 @MgO@PDA.…”

Multifunctional, flexible, and mechanically robust polyimide-MXene nanocomposites: a review

“…Hydrophilic PAA intercalates between MXene sheets via hydrogen bonding and polar interactions. In PI/MXene composites studied in this review, the most common fabrication method included mixing PAA and MXene dispersion, vacuum filtration and subsequent thermal imidization which resulted in thin films [57][58][59][60][61]. The final step was executed with either heating to high temperatures (up to 300 • C) or hot-pressing.…”

“…The thermal conductivity of the composite films was raised from 0.17 W m −1 K −1 for PI to 0.418 W m −1 K −1 of the composite with 5 wt% MXene. Cao et al[59] succeeded in increasing the dielectric constant of the PI/MXene composite to 7.8 with 7 wt% CTAB modified-MXene content.…”