Graphene oxide (GO) sheets have attracted increasingly high interest due to their relative ease of synthesis and water processability for a wide range of applications. Understanding how the sheets interact with each other is a crucial and foundational piece of knowledge guiding the production, processing, and use of GO in many applications. Here, we report that dehydration, such as by vacuum drying, triggers irreversible self-crosslinking of GO sheets and drastically alters their solution processability. Dehydrated GO films maintain structural integrity in water, and they can no longer redisperse as single layers even after agitation. At the bilayer level, dehydration fixes the stacked GO sheets together and prevents them from dissociation after sonication. Spectroscopical studies support the formation of new ester bonds, suggesting a condensation-esterification reaction between GO sheets. This new insight about a fundamental property of GO sheets should have broad implications in how the material should be processed and used.

氧化石墨烯 (GO) 片材因其相对易于合成和水加工性而受到越来越多的关注，适用于广泛的应用。了解工作表如何相互交互是指导 GO 在许多应用中的生产、加工和使用的关键和基础知识。在这里，我们报告了脱水，例如通过真空干燥，触发了 GO 片材的不可逆自交联，并极大地改变了它们的溶液加工性能。脱水的 GO 薄膜在水中保持结构完整性，即使在搅拌后它们也不能再分散为单层。在双层水平，脱水将堆叠的 GO 片固定在一起，并防止它们在超声处理后解离。光谱研究支持形成新的酯键，表明GO片材之间发生缩合 - 酯化反应。这种关于 GO 片材基本特性的新见解应该对如何处理和使用材料产生广泛的影响。