Preparation and Characterization of Transparent Polyimide Nanocomposite Films with Potential Applications as Spacecraft Antenna Substrates with Low Dielectric Features and Good Sustainability in Atomic-Oxygen Environments

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2021-07, Vol.11 (8), p.1886
• Main Authors: Zhang, Yan, Wu, Bo-han, Wang, Han-li, Wu, Hao, An, Yuan-cheng, Zhi, Xin-xin, Liu, Jin-gang
• Format: Article
• Language: English
• Subjects: antenna; Antennas; atomic oxygen; Dielectric constant; Dielectric properties; Dissipation factor; Earth orbits; Electrical properties; Erosion resistance; Fourier transforms; Kapton (trademark); Low earth orbits; Nanocomposites; Nitrogen; Oxygen; Parameters; Polyhedral oligomeric silsesquioxane; Polyimide resins; polyimide substrate; Polymers; POSS; Radiation; Spacecraft; Spacecraft antennas; Spectrum analysis; Substrates; Survivability; Sustainability
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano11081886

Optically transparent polyimide (PI) films with good dielectric properties and long-term sustainability in atomic-oxygen (AO) environments have been highly desired as antenna substrates in low earth orbit (LEO) aerospace applications. However, PI substrates with low dielectric constant (low-Dk), low dielectric dissipation factor (low-Df) and high AO resistance have rarely been reported due to the difficulties in achieving both high AO survivability and good dielectric parameters simultaneously. In the present work, an intrinsically low-Dk and low-Df optically transparent PI film matrix, poly[4,4′-(hexafluoroisopropylidene)diphthalic anhydride-co-2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane] (6FPI) was combined with a nanocage trisilanolphenyl polyhedral oligomeric silsesquioxane (TSP-POSS) additive in order to afford novel organic–inorganic nanocomposite films with enhanced AO-resistant properties and reduced dielectric parameters. The derived 6FPI/POSS films exhibited the Dk and Df values as low as 2.52 and 0.006 at the frequency of 1 MHz, respectively. Meanwhile, the composite films showed good AO resistance with the erosion yield as low as 4.0 × 10−25 cm3/atom at the exposure flux of 4.02 × 1020 atom/cm2, which decreased by nearly one order of magnitude compared with the value of 3.0 × 10−24 cm3/atom of the standard PI-ref Kapton® film.