Tritt-Goc Jadwiga, Knapkiewicz Magdalena, Harmata Piotr, Herman Jakub, Bielejewski Michał
Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznan, Poland.
Institute of Chemistry, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland.
Materials (Basel). 2024 Oct 19;17(20):5106. doi: 10.3390/ma17205106.
Using liquid crystals in near-infrared applications suffers from effects related to processes like parasitic absorption and high sensitivity to UV-light exposure. One way of managing these disadvantages is to use deuterated systems. The combined H and H nuclear magnetic resonance relaxometry method (FFC NMR), dielectric spectroscopy (DS), optical microscopy (POM), and differential scanning calorimetry (DSC) approach was applied to investigate the influence of selective deuteration on the molecular dynamics, thermal properties, self-organization, and electric-field responsiveness to a 4'-pentyl-4-biphenylcarbonitrile (5CB) liquid crystal. The NMR relaxation dispersion (NMRD) profiles were analyzed using theoretical models for the description of dynamics processes in different mesophases. Obtained optical textures of selectively deuterated 5CB showed the occurrence of the domain structure close to the I/N phase transition. The dielectric measurements showed a substantial difference in switching fields between fully protonated/deuterated 5CB and selectively deuterated molecules. The DSC thermograms showed a more complex phase transition sequence for partially deuterated 5CB with respect to fully protonated/deuterated molecules.
在近红外应用中使用液晶会受到诸如寄生吸收等过程相关的影响，并且对紫外线照射高度敏感。解决这些缺点的一种方法是使用氘代体系。采用氢和氢联合核磁共振弛豫测量法（FFC NMR）、介电谱（DS）、光学显微镜（POM）和差示扫描量热法（DSC）来研究选择性氘代对4'-戊基-4-联苯甲腈（5CB）液晶的分子动力学、热性能、自组装以及电场响应性的影响。利用理论模型分析了核磁共振弛豫色散（NMRD）曲线，以描述不同中间相中的动力学过程。所获得的选择性氘代5CB的光学织构显示出在接近I/N相变处出现了畴结构。介电测量表明，完全质子化/氘代的5CB与选择性氘代分子之间的开关场存在显著差异。DSC热谱图显示，相对于完全质子化/氘代的分子，部分氘代的5CB具有更复杂的相变序列。
