Gosvami N N, Sinha S K, Hofbauer W, O'Shea S J
Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576.
J Chem Phys. 2007 Jun 7;126(21):214708. doi: 10.1063/1.2741538.
We have performed simultaneous force and conductivity measurement of hexadecane liquid confined between a conducting atomic force microscope tip and a graphite surface. Both the current and the force data reveal discrete solvation layering of the hexadecane near the surface. We typically observe that the current does not vary with load in a simple way as the layer closest to the surface is compressed, but increases markedly prior to the expulsion of material from the tip-sample gap. We infer that even for a nanoscale asperity there is conformation change of the confined hexadecane under the tip apex prior to squeeze out of the molecules.
我们对限制在导电原子力显微镜探针与石墨表面之间的十六烷液体进行了力和电导率的同步测量。电流和力数据均揭示了十六烷在表面附近的离散溶剂化分层现象。我们通常观察到，当最靠近表面的层被压缩时，电流不会随着负载以简单的方式变化，而是在材料从探针 - 样品间隙中被挤出之前显著增加。我们推断，即使对于纳米级的粗糙表面，在分子被挤出之前，探针尖端下方受限十六烷的构象也会发生变化。
