Stabilisers, such as surfactants, polymers and polyaromatic molecules, offer an effective way to produce graphene dispersions in water by Liquid Phase Exfoliation (LPE) without degrading the properties of graphene. In particular, pyrene derivatives provide better exfoliation efficiency than traditional surfactants and polymers. A stabiliser is expected to be relatively soluble in order to disperse hydrophobic graphene in water. Here, we show that exfoliation can also be achieved with insoluble pyrene stabilisers if appropriately designed. In particular, bis-pyrene stabilisers (BPSs) functionalised with pyrrolidine provide a higher exfoliation efficiency and percentage of single layers compared to traditional pyrene derivatives under the same experimental conditions. This is attributed to the enhanced interactions between BPS and graphene, provided by the presence of two pyrene binding groups. This approach is therefore attractive not only to produce highly concentrated graphene, but also to use graphene to disperse insoluble molecules in water. The enhanced adsorption of BPS on graphene, however, is reflected in higher toxicity towards human epithelial bronchial immortalized cells, limiting the use of this material for biomedical applications.

中文翻译：

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使用不溶性双-稳定剂增强石墨烯在水中的液相剥离

稳定剂，例如表面活性剂，聚合物和聚芳族分子，提供了一种通过液相剥离（LPE）在水中生产石墨烯分散体的有效方法，而不会降低石墨烯的性能。特别是，pyr衍生物比传统的表面活性剂和聚合物具有更好的剥离效率。为了将疏水性石墨烯分散在水中，预期稳定剂是相对可溶的。在这里，我们表明，如果设计适当，不溶性pyr稳定剂也可以实现去角质。特别是，在相同的实验条件下，与传统的pyr衍生物相比，用吡咯烷官能化的双py稳定剂（BPS）具有更高的剥落效率和单层百分比。这归因于BPS和石墨烯之间增强的相互作用，由两个pyr结合基团的存在提供。因此，该方法不仅对生产高浓度的石墨烯具有吸引力，而且对于使用石墨烯将不溶性分子分散在水中也很有吸引力。但是，BPS在石墨烯上的吸附增强反映在对人上皮支气管永生化细胞的更高毒性中，限制了该材料在生物医学应用中的使用。