Polyimide/polyoxometalate copolymer thin films: synthesis, thermal and dielectric properties

A mono‐lancunary keggin‐type decatungstosilicate (SiW 11 ) polyoxometalate (POM) modified by γ ‐aminopropyltriethoxysilane (KH550) was incorporated into polyimide (PI) through copolymerization. Nuclear magnetic resonance (NMR), fourier transition infrared spectroscopy (FTIR), and wide angle X‐ray diffraction (WAXD) were used to characterize the structure and composition of the polyoxometalate–organosilane hybrid (SiW 11 KH550) and PI/SiW 11 KH550 copolymers. The differential scanning calorimetry (DSC) studies indicate that the glass transition temperature ( T g ) of PI/SiW 11 KH550 copolymers increases from 330°C (for neat PI) to 409°C (for the copolymer sample with 10 wt% of SiW 11 KH550). Dielectric measurement showed that both the dielectric constant and the dielectric loss for the copolymer thin films decreased with the increase in SiW 11 KH550 content, and the dielectric constant and dielectric loss values decreased to 2.1 and 3.54 × 10 −3 , respectively, for the copolymer sample with 10 wt% of SiW 11 KH550. The incorporation of SiW 11 KH550 into polymer matrices is a promising approach to prepare PI films with a low dielectric constant and low dielectric loss.