Ladder Polyphenylsilsesquioxanes and Their Niobium–Siloxane Composite as Coating Materials: Spectroscopy and Atomic Oxygen Resistance Study

Abstract

In order to expand the range of materials that can be used in outer space and in development of small spacecraft, ladder polyphenylsilsesquioxanes with different molar weights and the Nb-siloxane composites based on them were studied. The properties of the polymer films were studied, including tests in an oxygen plasma flow. Both initial and filled ladder polymers feature extremely low erosion coefficients in the region of 10–26 cm3/atom O at a high fluence of atomic oxygen of 1.0 × 1021 atom O/cm2. Ladder polyphenylsilsesquioxane films irradiated with atomic oxygen (AO) retain their integrity, do not crack, and exhibit good optical properties, in particular, a high transmittance. The latter slightly decreases during AO exposure. The Nb-siloxane filling retains the AO resistance and slight decrease in optical transmission due to diffuse scattering on the formed Nb-[(SiO)x] nanoparticles. Ladder polyphenylsilsesquioxanes demonstrate their suitability for creating protective, optically transparent coatings for small spacecraft that are resistant to the erosive effects of incoming oxygen plasma.

Recent progress in ladder-like polysilsesquioxane: synthesis and applications

“…137 Additionally, they reported the synthesis of tricyclic ladder siloxane through intramolecular cyclization of Janus rings in the presence of B(C 6 F 5 ) 3 . 138–143 This method has broadened the scope of ladder siloxanes by incorporating more siloxane units into the ring compared to traditional 6-8-6 or 8-8-8 membered-ring systems. Although this differs from polysilsesquioxanes, the focus of our review, it provides insight into researchers' approaches on ladder-type siloxanes.…”