Highly Organized Smectic-like Packing in Vapor-Deposited Glasses of a Liquid Crystal

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• 作者：Ankit GujralJaritza Gómez ; Jing Jiang ; Chengbin Huang ; Kathryn A. O’HaraMichael F. Toney ; Michael L. Chabinyc ; Lian Yu ; M. D. Ediger
• 刊名：Chemistry of Materials
• 出版年：2017
• 出版时间：January 24, 2017
• 年：2017
• 卷：29
• 期：2
• 页码：849-858
• 全文大小：601K
• ISSN：1520-5002

文摘

Glasses of a model smectic liquid crystal-forming molecule, itraconazole, were prepared by vapor deposition onto substrates with temperatures ranging from T_substrate = 0.78T_g to 1.02T_g, where T_g (=330 K) is the glass transition temperature. The films were characterized using X-ray scattering techniques. For T_substrate near and below T_g, glasses with layered smectic-like structures can be prepared and the layer spacing can be tuned by 16% through the choice of T_substrate. Remarkably, glasses prepared with T_substrate values above T_g exhibit levels of structural organization much higher than that of a thermally annealed film. These results are explained by a mechanism based upon a preferred molecular orientation and enhanced molecular motion at the free surface, indicating that molecular organization in the glass is independent of the anchoring preferred at the substrate. These results suggest new strategies for optimizing molecular packing within active layers of organic electronic and optoelectronic devices.