Reactive Molecular
Dynamics Study of the Mechanism
and Effect of Various Protective Coatings on the Protection of Polyimide
Antierosion from Atomic Oxygen
posted on 2024-01-04, 01:29authored byDahai Wei, Fanlin Zeng, Jianzheng Cui
Polyimide (PI), due to its exceptional performance, is
commonly
utilized in spacecraft. However, when such polymers are used in spacecraft
navigating low Earth orbit, they are exposed to atomic oxygen (AO)
that can cause the polymer to decompose. A protective coating method
is a more effective way to safeguard the polymer from erosion caused
by AO. This study employs the molecular dynamics simulation based
on the reaction force field to investigate the protective effects
of various coatings, including polydimethylsiloxane (PDMS), graphene
(Gr), polytetrafluoroethylene (PTFE), and the (0 0 1), (0 1 1), and
(1 1 1) surfaces of SiO2. The results indicate that the
protective performance of the (0 1 1) surface is superior to that
of the (0 0 1) and (1 1 1) surfaces. Moreover, protective coatings
are classified into three categories based on different protective
mechanisms: rebound, absorption, and sacrificial. The protective effectiveness
of coatings depends on their anti-AO performance and ability to combine
with the substrate. Gr displays exceptional anti-AO properties and
can effectively shield the substrate from AO erosion. Silicone-based
coatings have a superior ability to adhere to PI substrates, and PDMS
is an excellent choice for protective coatings. This paper offers
guidance for the protective coating method of PIs against AO erosion.