Gómez Jaritza, Jiang Jing, Gujral Ankit, Huang Chengbin, Yu Lian, Ediger M D
Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China.
Soft Matter. 2016 Mar 21;12(11):2942-7. doi: 10.1039/c5sm02944a.
Physical vapor deposition (PVD) has been used to prepare glasses of itraconazole, a smectic A liquid crystal. Glasses were deposited onto subtrates at a range of temperatures (Tsubstrate) near the glass transition temperature (Tg), with Tsubstrate/Tg ranging from 0.70 to 1.02. Infrared spectroscopy and spectroscopic ellipsometry were used to characterize the molecular orientation using the orientational order parameter, Sz, and the birefringence. We find that the molecules in glasses deposited at Tsubstrate = Tg are nearly perpendicular to the substrate (Sz = +0.66) while at lower Tsubstrate molecules are nearly parallel to the substrate (Sz = -0.45). The molecular orientation depends on the temperature of the substrate during preparation, allowing layered samples with differing orientations to be readily prepared. In addition, these vapor-deposited glasses are macroscopically homogeneous and molecularly flat. We interpret the combination of properties obtained for vapor-deposited glasses of itraconazole to result from a process where molecular orientation is determined by the structure and dynamics at the free surface of the glass during deposition. Vapor deposition of liquid crystals is likely a general approach for the preparation of highly anisotropic glasses with tunable molecular orientation for use in organic electronics and optoelectronics.
物理气相沉积（PVD）已被用于制备伊曲康唑玻璃，伊曲康唑是一种近晶A液晶。在接近玻璃化转变温度（Tg）的一系列温度（Tsubstrate）下将玻璃沉积到基板上，Tsubstrate/Tg的范围为0.70至1.02。使用红外光谱和光谱椭偏仪，通过取向序参数Sz和双折射来表征分子取向。我们发现，在Tsubstrate = Tg时沉积的玻璃中的分子几乎垂直于基板（Sz = +0.66），而在较低的Tsubstrate下分子几乎平行于基板（Sz = -0.45）。分子取向取决于制备过程中基板的温度，这使得具有不同取向的层状样品易于制备。此外，这些气相沉积的玻璃在宏观上是均匀的，分子是平整的。我们将伊曲康唑气相沉积玻璃所获得的性能组合解释为一个过程的结果，在该过程中，分子取向由沉积过程中玻璃自由表面的结构和动力学决定。液晶的气相沉积可能是制备具有可调分子取向的高度各向异性玻璃的通用方法，用于有机电子学和光电子学。
