Electro-optical properties and frequency response of polymer-dispersed liquid crystal gratings doped with multi-walled carbon nanotubes
Electro-optical properties and frequency response of polymer-dispersed liquid crystal gratings doped with multi-walled carbon nanotubes
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DOI：
10.1007/s10853-021-06104-9
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发表时间：
2021-04-23
影响因子：
4.5
通讯作者：
Zhuang, Songlin
中科院分区：
文献类型：
--
作者：
Liu, Yourong;Shen, Jinrong;Zhuang, Songlin
基于特定纳米管的麦克斯韦-瓦格纳效应，建立了全息聚合物分散液晶(H-PDLC)的最低驱动电压模型。讨论了多壁碳纳米管(MWCNTs)的掺杂浓度和分布对转折点频率的影响。多壁碳纳米管可以有效地调节光栅的驰豫频率，增大其液滴尺寸，降低其介电常数。实验结果表明，在5 kHz频率下，可开关布拉格光栅的衍射效率和阈值电压分别达到91%和0.77 Vµm(-1)。通过对比实验和模拟结果，得到了碳纳米管在液晶区和聚合物区的质量分配比。研究发现，多壁碳纳米管在聚合过程中扩散到液晶区，选择合适的驱动频率和掺杂浓度可以使驱动电压最小。这项工作为研究纳米粒子在可开关光栅中的动态范围、光学调谐和聚合动力学提供了参考。
In this paper, a model developed for establishing the lowest possible driving voltage of Holographic polymer-dispersed liquid crystal (H-PDLC) based on the Maxwell-Wagner effect doped with specific nanotubes. The dependences of the turning point frequency on the doping concentration and the distribution of multi-walled carbon nanotubes (MWCNTs) are discussed. The MWCNTs can effectively adjust the relaxation frequency of grating, increase its LC droplet size, and decrease its dielectric permittivity. The diffraction efficiency and threshold voltage of the prepared switchable Bragg grating were found to reach 91% and 0.77 V mu m(-1), respectively, at 5 kHz. By comparing the results of experiments and simulations, we obtained the mass distribution ratio of MWCNTs in the LC and polymer regions. It was found that the MWCNTs diffuse into the LC regions during the polymerization process, and the use of a suitable driving frequency and doping concentration can minimize the driving voltage. This work provides a reference for studying the dynamic range optical tuning and polymerization kinetics of nanoparticles in switchable gratings.