In this work, polydopamine (PDA) and polyetheramine D230 were selected to construct the PDA-D230 interphase between the carbon fiber (CF) and epoxy matrix. Density functional theory (DFT) and molecular dynamics (MD) simulations were performed to explore the interface enhancement mechanisms of a carbon fiber reinforced polymer (CFRP) with the PDA-D230 interphase from the molecular level. The adsorption characteristics of a PDA molecule on the CF surface were investigated using the DFT method. The results show that stronger π–π stacking interactions are formed due to the structure and orientation preference of the PDA molecule. The interfacial structures and properties of CFRP with the PDA-D230 interphase are derived from MD simulations. The PDA-D230 interphase on the CF surface induces stronger interfacial interaction energy, leading to the better load transfer between the CF and epoxy matrix. The existence of the PDA-D230 interphase on the CF surface can decrease the mean-square displacement (MSD) value and the free volume fraction of CFRP, which restricts the movement of epoxy atoms and inhibits the translational and rotational motion of epoxy chains. Compared with the epoxy using pristine CFs as reinforcement, the interfacial shear stress (ISS) of CFRP with the PDA-D230 interphase is improved by 13.1%. Our results provide valuable insights into the interface characteristics of CFRP with the PDA-D230 interphase, which are of great significance for exploring the strengthening mechanisms for CFRPs with the PDA-D230 interphase.

中文翻译：

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在分子水平上了解CFRP与聚多巴胺-聚醚胺界面的界面增强机制


在这项工作中，选择聚多巴胺（PDA）和聚醚胺D230在碳纤维（CF）和环氧树脂基体之间构建PDA-D230界面。通过密度泛函理论（DFT）和分子动力学（MD）模拟，从分子水平探讨了碳纤维增强聚合物（CFRP）与PDA-D230界面相的界面增强机制。采用DFT方法研究了PDA分子在CF表面的吸附特性。结果表明，由于 PDA 分子的结构和取向偏好，形成了更强的 π-π 堆积相互作用。 CFRP 与 PDA-D230 界面相的界面结构和性能来自 MD 模拟。 CF表面上的PDA-D230界面产生更强的界面相互作用能，从而导致CF和环氧树脂基体之间更好的载荷传递。 CF表面PDA-D230界面相的存在可以降低CFRP的均方位移（MSD）值和自由体积分数，从而限制环氧原子的运动并抑制环氧链的平移和旋转运动。与使用原始CF作为增强体的环氧树脂相比，具有PDA-D230界面的CFRP的界面剪切应力（ISS）提高了13.1%。我们的研究结果为了解CFRP与PDA-D230界面的界面特性提供了有价值的见解，这对于探索CFRP与PDA-D230界面的强化机制具有重要意义。