The Adsorption of hexacontane on hexagonal boron nitride

We have investigated the adsorption of hexacontane (C60 H122) on hexagonal boron nitride (hBN) using atomic force microscopy (AFM). The molecules can be deposited either by sublimation or from solution and form lamellar rows with dimensions of the order of 0.1 - 1 µm in three different rotational domains. High-resolution AFM images reveal that, similar to alkanes on graphite, the molecules are adsorbed parallel to the lattice vectors of hBN and we show using molecular mechanics that this corresponds to the lowest energy configuration. Lamellar rows with the same periodicity are observed even when several layers of hexacontane are deposited, although there is some orientational disorder in these multilayers. We also observe heat-induced modification of hexacontane including re-crystallization. We compare our results with recent X-ray studies of alkane adsorption on hBN and discuss the possible role of alkanes on steering molecular self-assembly on hBN.

我们利用原子力显微镜（atomic force microscopy, AFM）研究了六癸烷（hexacontane, C₆₀H₁₂₂）在六方氮化硼（hexagonal boron nitride, hBN）表面的吸附行为。这些分子可通过升华法或溶液法沉积，并在三个不同的旋转畴中形成尺寸约为0.1-1μm的层状排列。高分辨率AFM图像显示，与石墨表面的烷烃类似，六癸烷分子沿hBN的晶格矢量平行吸附；通过分子力学计算，我们证实这一构型对应最低能量状态。即使沉积多层六癸烷，仍能观察到具有相同周期性的层状排列，尽管这些多层结构中存在一定的取向无序性。我们还观察到热诱导的六癸烷改性现象，包括重结晶过程。我们将研究结果与近期关于烷烃在hBN表面吸附的X射线研究进行了对比，并探讨了烷烃在调控hBN表面分子自组装过程中的潜在作用。