Highly Homogeneous Polysiloxane Flexible Coating for Low Earth Orbital Spacecraft with Ultraefficient Atomic Oxygen Resistance and Self-Healing Behavior

Highly flexible atomic-oxygen (AO)-resistant coatings emerge as essential protective materials for low earth orbit (LEO) spacecraft. However, achieving synergistic characteristics of ultraefficient AO resistance, self-healing ability, and excellent stabilities remains a critical challenge. In this work, a flexible polysiloxane coating coupled with a highly homogeneous composition is a well-organized form used as the raw material of hexamethyldisiloxane (HMDSO). This siloxane coating displays excellent flexibility and interfacial strength verified by bending and thermal cycling experiments. After an AO irradiation experiment with the accumulated flux of 2.5 × 1022 atoms/cm2 (the equivalent of 5 years), the mass loss rate of the polysiloxane-coated Kapton film is less than 0.284 ± 0.044 mg/cm2, demonstrating long-life and high-reliability characteristics. In addition, this flexible coating displayed self-healing behavior due to the formation of SiO2-durable layers during the AO irradiation, which endows the polysiloxane coating with “stiff exterior, flexible interior” characteristics based on the high flexibility. Our work shows the actual application and great potential of flexible self-healing AO protective coatings in spacecraft and provides a useful strategy to design multifunctional barrier materials.