Molecular manipulator driven by spatial variation of liquid-crystalline order
Molecular manipulator driven by spatial variation of liquid-crystalline order
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DOI：
10.1038/nmat2853
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发表时间：
2010-10-01
期刊：
影响因子：
41.2
通讯作者：
Yamamoto, Jun
中科院分区：
文献类型：
--
作者：
Samitsu, Sadaki;Takanishi, Yoichi;Yamamoto, Jun
液晶中微米级杂质之间的集体长程相互作用是由液晶有序性的弹性变形引起的1 -8。对于相当小的聚合物杂质，相关的不是它们之间的弹性相互作用，而是标量有序参数S和聚合物浓度phi之间的耦合。这种耦合起源于局部分子相互作用，但由于总聚合物浓度在整个样品上是守恒的，因此变得长程。在这里，我们提出了一种新的机制，S的空间变化产生的力，介导的S和φ之间的耦合，运输纳米级聚合物杂质。我们已经设计了一个原型的分子操纵器，移动分子沿着空间变化的标量序参数，调制在一个可控的方式由点照明的偶氮苯掺杂的双相紫外光。我们还演示了使用的机械手的测量的各向异性扩散常数的聚合物在α相。该机械手可以控制聚合物浓度的空间变化，从而显示出用于混合软材料设计的希望。
Collective long-range interactions between micrometre-sized impurities in liquid crystals result from the elastic distortion of the liquid-crystalline order1-8. For substantially smaller polymeric impurities, what is relevant is not the elastic interaction between them but the coupling between the scalar nematic order parameter S and the polymer concentration phi. This coupling originates from local molecular interactions, but becomes long ranged because the total polymer concentration is conserved over the whole sample. Here, we propose a new mechanism by which the spatial variation of S generates a force, mediated by the coupling between S and phi, that transports nanoscale polymeric impurities. We have designed a prototype of a molecular manipulator that moves molecules along spatial variations of the scalar order parameter, modulated in a controlled manner by spot illumination of an azobenzene-doped nematic phase with ultraviolet light. We also demonstrate the use of the manipulator for the measurement of the anisotropic diffusion constant of a polymer in the nematic phase. The manipulator can control the spatial variation of the polymer concentration, thus showing promise for use in the design of hybrid soft materials.