Enhanced dielectric properties induced by the rational design of interfacial buffer layer in MoS2/poly(arylene ether nitrile) composites

As the vital components of organic film capacitors, polymer-based dielectric composites present challenges in the simultaneous pursuit of toughness, high dielectric constant, low dielectric loss, and significant thermal stability. In this work, poly(arylene ether nitrile) (PEN) with pendant carboxy groups (PEN-COOH) was achieved through nucleophilic substitution, and then grafted onto the surface of molybdenum disulfide (MoS2) as interfacial buffer layer, forming PEN-COOH@MoS2 filler. Subsequently, the PEN-COOH@MoS2 was filled in PEN to fabricate PEN-COOH@MoS2/PEN composite dielectric films. The interfacial interaction between PEN-COOH@MoS2 and PEN was improved by π-π conjugation, hydrogen bonding interactions and similar polymer structure of PEN-COOH with PEN, triggering multiple interfaces polarization and delocalization effect. Consequently, the PEN-COOH@MoS2/PEN composite films were endowed an improving dielectric constant without largely sacrificing the dielectric loss compared with pure PEN film, synchronously maintaining better flexibility and thermal stability. Particularly, the as-prepared composite with 15 wt% PEN-COOH@MoS2 loading possessed a dielectric constant of 7.53 at 1 kHz and increased by 97.12% compared with pure PEN film (3.82). Synchronously, the dielectric loss (0.0211 at 1 kHz) was still maintained the same order of magnitude as the PEN matrix. This work demonstrates that using PEN-COOH for interface engineering between polymers and semiconductors is a feasible alternative to manufacture dielectric materials and has achieved outstanding comprehensive results.