From Event: SPIE Organic Photonics + Electronics, 2016
Transport of fluids and particles at the microscale is an important theme both in fundamental and applied science. We demonstrate how an advanced approach to photo-induced alignment of liquid crystals can be used to generate nonlinear electrokinetics. The photoalignment technique is based on irradiation of a photosensitive substrate with light through nanoaperture arrays in metal films. The resulting pattern of surface alignment induces predesigned 2D and 3D distortions of local molecular orientation. In presence of a static electric field, these distortions generate spatial charge and drive electrokinetic flows of the new type, in which the velocities depend on the square of the applied electric field. The patterned liquid crystal electrolyte converts the electric energy into the flows and transport of embedded particles of any type (fluid, solid, gaseous) along a predesigned trajectory, posing no limitation on the electric nature (charge, polarizability) of these particles and interfaces. The patterned liquid crystal electrolyte induces persistent vortices of controllable rotation speed and direction that are quintessential for micro- and nanoscale mixing applications.
Oleg D. Lavrentovich, Chenhui Peng, Yubing Guo, Sergij V. Shiyanovskii, and Qi-Huo Wei, "Controlling statics and dynamics of colloids by photo-patterned liquid crystals
(Conference Presentation)," Proc. SPIE 9940, Liquid Crystals XX, 99400Q (Presented at SPIE Organic Photonics + Electronics: August 29, 2016; Published: 2 November 2016); https://doi.org/10.1117/12.2236421.5167077761001.
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