Edge-to-Edge Assembly of Graphene Oxide Flakes as Nanometric Anticorrosive Barriers for Heritage Metals

Graphene oxide (GO) is a highly promising candidate for protecting ancient and historic metallic artifacts, as it can form ultrathin, durable films that cause minimal visual alteration. However, producing a uniform, defect-free coating remains a major challenge. In this work, we propose an effective strategy to overcome this limitation by combining Langmuir–Blodgett deposition with systematic tailoring of the nanomaterial properties of GO flakes. We demonstrate that the lateral size, polydispersity, and oxidation state are critical parameters governing assembly at the air–water interface. The synergy between these factors enables the formation of highly ordered continuous monolayers with near-perfect edge-to-edge packing and strong interfacial adhesion. These engineered films act as superior nanometric barriers, providing exceptional corrosion resistance while inducing negligible color change. Notably, the coatings exhibit remarkable adaptability, even on rough and heterogeneous surfaces, as demonstrated on corroded copper-based alloys. When applied to a historic copper coin, the GO coating effectively inhibits further corrosion while preserving the original appearance, confirming its suitability as an innovative protective treatment for the conservation of cultural heritage metals.