Exploring the Effects of Trifluoromethyl Group on the Molecular Structure and Properties of Polyimides

Abstract To realize high integration and miniaturization of electronic components, the microelectronics field is in urgent need of low dielectric constant materials with high mechanical properties. In this work, a series of fluorinated polyimide films were prepared, the free volume of fluorinated polyimide was calculated using molecular dynamics simulations, and the effect of the trifluoromethyl structure on the thermal, mechanical, and dielectric properties of polyimide (PI) films was discussed. The results show that introducing a trifluoromethyl structure can significantly reduce the dielectric constant and water uptake of PI films. Molecular dynamics simulation results show that the introduction of trifluoromethyl structure increased the free volume fraction of PI, and the films prepared by HFPBDA and 6FDA showed the best performance, with dielectric constant and water uptake were 3.21 and 0.57%, respectively. The tensile strength and elongation at break were 102 MPa and 13.0%, respectively.