Interfacial Non-Covalent Functionalization for Interlayer Shear Mitigation and Structural Assembly of Macro-Scale Single-Crystal Graphene Megastructures

# Interfacial Non-Covalent Functionalization for Interlayer Shear Mitigation and Structural Assembly of Macro-Scale Single-Crystal Graphene Megastructures ### DescriptionThe transition of monolayer graphene synthesis into macro-scale engineering applications—such as Earth-based space elevator tethers and rigid vacuum buoyancy vessels—is fundamentally limited by interlayer superlubricity and structural assembly defects. When pristine sheets are layered, independent interlayer slippage (shear lag) degrades the macroscopic tensile properties, causing premature structural failure. Furthermore, conventional structural bonding or cross-linking methodologies introduce covalent disruptions that ruin the underlying sp² lattice. This technical note details an active chemical and geometric framework designed to bypass these limitations within an automated orbital manufacturing pipeline. We propose the application of gas-phase polycyclic aromatic hydrocarbon (PAH) derivatives to act as a spatial "Tetra-Etch" analog. These molecules anchor to pristine graphitic surfaces via non-destructive 𝛑-𝛑 electronic stacking, leaving the underlying single-crystal sp² conjugation intact. Perpendicular reactive chemical tails (e.g., amine or hydroxyl functional groups) then covalently link with adjacent interfaces to form high-density molecular "cleats" that uniformly distribute applied mechanical loads. This mechanism is evaluated across two planetary infrastructure configurations:1. Macroscopic Tensile Tethers: A structural performance comparison between flat multi-layered ribbons and concentric multi-walled tubular cables to optimize load transfer and shear mitigation.2. Modular Vacuum Buoyancy Blocks: Monolithic cold-welding assembly of macro-honeycomb cells in Low Earth Orbit (LEO) to construct non-deflating, permanent stratospheric lifting platforms. Shared openly as public domain prior art (CC0) to establish a baseline design architecture for macro-scale aerospace megastructures.