Polarization Effects of Fluorine on the Relative Permittivity in Polyimides

Synthesis and Characterization of Polyimide from 4,4’-Diamino diphenyl ether having Substituents at 2,2’-position

“…A positive correlation was observed as previously reported [13,14]. The refractive indices (n) of polyimides PI3x were measured, and dielectric constants ( ε cal ) were estimated using the empirical relationship; ε cal = 1.1 n 2 [14,15] derive from the relationship among velocity of light (C), dielectric constant (ε) and magnetic permeability (μ), C = , and compared with those of PI1x and PI2x (Figure 3-a). The values ofε cal for PI3x was in the range of 2.93-3.21, and the value of PI3i from 4,4'-(hexafluoroisopropylidene)-diphthalic an-hydride i was the lowest.…”

Polymer Dielectric Materials

“…This has been exemplified by the opposite effect in indiscriminately subsitituting fluorine atom into a polyimide chain resulting in an increase in otherwise low dielectric constant material. [11] There is no dipole polarization contribution for non-polar polymers as found in polar polymers. This different mode of mechanism lead to the resonance spectra in the case of electronic polarization which occur at frequency beyond 10 12 Hz.…”

Fundamental insight on developing low dielectric constant polyimides

“…The polarizability (a) of each species is generally additive (i.e., a = a electronic + a atomic + a dipolar ) and can be combined with the Clausius-Mossotti relationship to estimate the contribution of each polarization mode to the dielectric constant (e) as shown in equation (1) [11].…”