1. Molecular structure of polyhedral oligomeric silsesquioxane (POSS) ^[24]

2. PI surface modification to form polyamic acid: NaOH hydrolysis of PI (Step 1) to form sodium salt of polyamic acid followed by acidification (Step 2) to form polyamic acid^[50]

3. SEM images of AO exposed (effective fluence ~2.0×10²⁰atoms/cm²) samples: untreated samples^[52,53] (a) masked section and (b) exposed section, images of Implantox^TM treatment being (c) masked and (d) exposed sections, and AO exposed (e) Implantox-treated section and (f) untreated sections

4. SEM images of AO exposed (effective fluence~ 2.0×10²⁰ atoms/cm²) sample surfaces morphology^[56]: untreated original PI and (b) SiO₂ coated PI

5. Initial (left, t=0) and final (right, t=35 ps) simulation snapshots of different PI protection system under AO impact^[71]:PI-grafted (a) 15wt% POSS and (b) 30wt% POSS; 15wt% graphene (c) randomly oriented and (d) aligned

6. Potential barrier of an O atom permeating into interlayer of double-layer graphene with matched divacancy defect^[74]