Luk Yan-Yeung, Abbott Nicholas L
Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
Science. 2003 Aug 1;301(5633):623-6. doi: 10.1126/science.1084527.
Electrochemical control of the oxidation state of ferrocene-decorated electrodes leads to surface-driven changes in the orientations of thermotropic liquid crystals. When the electrodes possess nanometer-scale topography, voltages of 0.0 to 0.3 volts (versus a counter electrode in a two-electrode cell) can drive changes in the orientation of the liquid crystals in the plane and/or out of the plane of the electrodes. Electrodes not supporting ferrocene do not lead to surface-driven orientational transitions. The in-plane transitions are driven by the reorganization of the monolayer of ferrocene upon oxidation of ferrocene to ferrocenium. The out-of-plane transition reflects a dielectric coupling between the liquid crystal and the diffuse part of an electrical double layer that evolves upon oxidation of ferrocene to ferrocenium. These results suggest new ways to couple the orientations of liquid crystals to chemical and electrical stimuli in electro-optical devices and chemical sensors.
对二茂铁修饰电极的氧化态进行电化学控制会导致热致液晶取向发生表面驱动的变化。当电极具有纳米级形貌时，0.0至0.3伏的电压（相对于两电极电池中的对电极）可驱动液晶在电极平面内和/或平面外的取向变化。不负载二茂铁的电极不会导致表面驱动的取向转变。平面内的转变是由二茂铁氧化为二茂铁鎓时二茂铁单层的重组驱动的。平面外的转变反映了液晶与双电层扩散部分之间的介电耦合，这种耦合在二茂铁氧化为二茂铁鎓时会发生变化。这些结果为在电光器件和化学传感器中将液晶取向与化学和电刺激耦合提供了新方法。
