Enhancement of dielectric properties of poly(dimethyl siloxane) copolymer elastomer using chemically modified metal-organic frameworks

The urgent demand to construct high-performance electromechanical transducers requires elastomers with excellent dielectric properties, hence poly (dimethyl siloxane) copolymer elastomer composite films with high dielectric constant and low dielectric loss have been successfully prepared in this work. A chemically modified metal-organic framework (KPPMOF) was chosen to compensate for the low dielectric constant of the poly (dimethyl siloxane) copolymer (D-PDMS) itself. After a series of tests, results show that the dielectric constant of 1.51 vol% KPPMOF/D-PDMS composite achieves 29.7 at 100 Hz, which is 10.7 times higher compared to the pure D-PDMS, while the loss at 100 Hz is only 0.05. The introduction of KPPMOF further increases the dielectric strength of composites, reaching a maximum of 124.14 MV/m, which is 1.8 times that of pure D-PDMS. Furthermore, the enhancement of the dielectric constant of composites is discussed in detail by means of micro-capacitor theory and Maxwell's polarization theory, while the root cause of the variation in dielectric loss factor at low frequencies is investigated using the Cole-Cole model. Herein we used polyaniline modified metal organic framework MIL-101 (Cr) material and poly (dimethyl siloxane) copolymer elastomer to prepare composite films, while polydopamine and KH550 modified PMOF to enhance its dispersion in poly (dimethyl siloxane) copolymer and further reduce the dielectric loss. The composite prepared with a filler content of 1.51 vol% has a dielectric constant of 29.7 and a dielectric loss of 0.05 at 100 Hz and room temperature. [Display omitted] •Metal-organic framework materials with excellent dispersion in the organic phase was prepared.•The composites showed high dielectric constant (29.7) and low loss (0.05) at 100Hz.•The mechanism of increasing the dielectric constant and dielectric strength was systematically investigated.