CNR-INFM LiCryL, c/o Physics Department, University of Calabria, 87036 Rende (CS), Italy.
Phys Rev Lett. 2009 Oct 16;103(16):167801. doi: 10.1103/PhysRevLett.103.167801. Epub 2009 Oct 12.
Using an atomic force microscopy, we have measured the separation dependence of the force between an atomically flat mica sheet and a micrometer-sized glass sphere immersed in the nematic liquid crystal. As the mica surface induces a strong parallel alignment and the treated glass sphere induces a strong perpendicular alignment on the liquid crystal, a repulsive force is observed due to the elastically deformed nematic liquid crystal. We observe that below a critical separation d(th) approximately 10 nm, the system undergoes a structural transition, thus relaxing the distortion. The results are interpreted within the eigenvalue exchange mechanism using the Landau-de Gennes tensorial approach.
我们使用原子力显微镜测量了原子级平坦云母片和浸没在向列液晶中的微米级玻璃球之间的力随分离距离的变化关系。由于云母表面强烈地诱导出平行排列，而经过处理的玻璃球强烈地诱导出垂直排列，因此在弹性变形的向列液晶中会观察到排斥力。我们观察到，在临界分离距离 d(th)约 10nm 以下，系统会经历结构转变，从而松弛变形。结果使用 Landau-de Gennes 张量方法的特征值交换机制进行了解释。
