Unraveling the self-reinforcing mechanism of atomic oxygen resistant polysiloxane coatings

Organosilicon coatings with electrically insulating and high/low temperature stability have been successfully employed to resist atomic oxygen (AO) irradiation for low Earth orbit spacecraft. Particularly, it displays a re-enhanced AO resistance due to the surface reconstruction, yet, such transformation and persistence lacks a mechanistic basis at atomic level in establishing structure-property relationships for guiding next-generation coating. Herein, an AO-resistance polysiloxane coating was successfully prepared, then, correlated via multiscale analysis, it was found that the coating evolved into an inorganic (SiO x )-organic (SiO x C y H z ) hybrid structure, and this highly flexible structure could be maintained for a longer period of time by relying on more organic components, featuring as a dense “nano fencing” hybrid structure to resist AO erosion and reduce cracks. These findings well explain the self-reinforcing mechanisms of polysiloxane coating at atomic level and provide a reference for the design of long-lived protective coatings.