Abstract Attachment of amine-bearing molecules, denoted surface grafted molecules (SGMs), onto the surface of carbon fibre has been previously shown to enhance interfacial interactions at the carbon fibre/epoxy interface. However, the design principles inherent to optimising this enhancement are not yet established. Here, we investigate the influence of SGM design criteria on the interfacial mechanical response for three types of SGM via predictions based on molecular dynamics simulations, and by experimental measurements. The SGMs are covalently grafted to the graphitic fibre surface via in situ generated and decomposed phenyl diazo salts. All three SGMs possess a phenyl ring as the surface attachment point, and differ by the number and/or position (meta or para) of the amine-terminated side-chain(s) attached to the ring. The single-chain meta-substituted SGM produces the least interfacial enhancement, while the double-chain meta-substituted SGM enhances the interfacial shear strength by 29% relative to the control. In contrast, the single-chain para-SGM performs almost comparably to the double-chain meta-SGM. Our modelling predictions recover this trend and offer molecular-scale explanations for these findings, providing guidance in the design of effective surface-tailoring strategies to realise enhancements in the shear response of carbon fibre–epoxy interfaces.

中文翻译：

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与环氧树脂交联的功能化碳纤维表面之间界面相互作用的预测模型

摘要 含胺分子（表示为表面接枝分子 (SGM)）附着在碳纤维表面上先前已被证明可增强碳纤维/环氧树脂界面处的界面相互作用。但是，优化此增强功能的固有设计原则尚未建立。在这里，我们通过基于分子动力学模拟的预测和实验测量来研究 SGM 设计标准对三种类型 SGM 的界面机械响应的影响。SGMs 通过原位生成和分解的苯基重氮盐共价接枝到石墨纤维表面。所有三种 SGM 都具有苯环作为表面连接点，并且连接到环上的胺封端侧链的数量和/或位置（间位或对位）不同。单链间位取代的 SGM 产生的界面增强最小，而双链间位取代的 SGM 使界面剪切强度相对于对照提高了 29%。相比之下，单链 para-SGM 的表现几乎与双链 meta-SGM 相当。我们的建模预测恢复了这一趋势，并为这些发现提供了分子尺度的解释，为有效的表面定制策略的设计提供了指导，以实现碳纤维-环氧树脂界面剪切响应的增强。