Tsuji Yuta, Kitamura Yasuhiro, Someya Masao, Takano Toshihiko, Yaginuma Michio, Nakanishi Kohei, Yoshizawa Kazunari
Institute for Materials Chemistry and Engineering and IRCCS, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan.
Mitsubishi Gas Chemical Company Inc., Chiyoda-ku, Tokyo 100-8324, Japan.
ACS Omega. 2019 Mar 1;4(3):4491-4504. doi: 10.1021/acsomega.9b00129. eCollection 2019 Mar 31.
Adhesion interaction of epoxy resin with the basal surfaces of h-BN and graphite is investigated with the first-principles density functional theory calculations in conjunction with the dispersion correction. The h-BN/epoxy and graphite/epoxy interfaces play an important role in producing nanocomposite materials with excellent thermal dissipation properties. The epoxy resin structure is simulated by using four kinds of fragmentary models. Their structures are optimized on the h-BN and graphite surfaces after an annealing simulation. The distance between the epoxy fragment and the surface is about 3 Å. At the interface between h-BN and epoxy resin, no H-bonding formation is observed, though one could expect that the active functional groups of epoxy resin, such as hydroxyl (-OH) group, would be involved in a hydrogen-bonding interaction with nitrogen atoms of the h-BN surface. The adhesion energies for the two interfaces are calculated, showing that these two interfaces are characterized by almost the same strength of adhesion interaction. To obtain the adhesion force-separation curve for the two interfaces, the potential energy surface associated with the detachment of the epoxy fragment from the surface is calculated with the help of the nudged elastic band method and then the adhesion force is obtained by using either the Morse-potential approximation or the Hellmann-Feynman force calculation. The results from both methods agree with each other. The maximum adhesion force for the h-BN/epoxy interface is as high as that for the graphite/epoxy interface. To better understand this result, a force-decomposition analysis is carried out, and it has been disclosed that the adhesion forces working at both interfaces mainly come from the dispersion force. The trend of increase in the parameters used for the dispersion correction for the atoms included in the h-BN or graphite surface is in the order: N < C < B, which reasonably explains why the strengths of the dispersion forces operating at the two interfaces are similar. Also, the electron localization function analysis can explain why the h-BN surface cannot form an H bond with the hydroxyl group in epoxy resin.
采用第一性原理密度泛函理论计算并结合色散校正，研究了环氧树脂与六方氮化硼（h-BN）和石墨基底表面的粘附相互作用。h-BN/环氧树脂和石墨/环氧树脂界面在制备具有优异热耗散性能的纳米复合材料中起着重要作用。使用四种片段模型模拟环氧树脂结构。经过退火模拟后，它们的结构在h-BN和石墨表面上得到优化。环氧片段与表面之间的距离约为3 Å。在h-BN与环氧树脂的界面处，未观察到氢键形成，尽管人们可能预期环氧树脂的活性官能团，如羟基（-OH）基团，会与h-BN表面的氮原子发生氢键相互作用。计算了两个界面的粘附能，结果表明这两个界面的粘附相互作用强度几乎相同。为了获得两个界面的粘附力-分离曲线，借助推挤弹性带方法计算与环氧片段从表面分离相关的势能面，然后使用莫尔斯势近似或赫尔曼-费曼力计算得到粘附力。两种方法的结果相互吻合。h-BN/环氧树脂界面的最大粘附力与石墨/环氧树脂界面的一样高。为了更好地理解这一结果，进行了力分解分析，结果表明在两个界面起作用的粘附力主要来自色散力。用于h-BN或石墨表面所含原子的色散校正参数的增加趋势为：N < C < B，这合理地解释了在两个界面起作用的色散力强度为何相似。此外，电子定域函数分析可以解释为什么h-BN表面不能与环氧树脂中的羟基形成氢键。
