skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Nematic-like stable glasses without equilibrium liquid crystal phases

Abstract

We report the thermal and structural properties of glasses of posaconazole, a rod-like molecule, prepared using physical vapor deposition (PVD). PVD glasses of posaconazole can show substantial molecular orientation depending upon the choice of substrate temperature, Tsubstrate, during deposition.Ellipsometry and IR measurements indicate that glasses prepared at Tsubstrate very near the glass transition temperature (Tg) are highly ordered. For these posaconazole glasses, the orientation order parameter is similar to that observed in macroscopically aligned nematic liquid crystals, indicating that the molecules are mostly parallel to one another and perpendicular to the interface. To our knowledge, these are the most anisotropic glasses ever prepared by PVD from a molecule that does not form equilibrium liquid crystal phases. These results are consistent with a previously proposed mechanism in which molecular orientation in PVD glasses is inherited from the orientation present at the free surface of the equilibrium liquid. This mechanism suggests that molecular orientation at the surface of the equilibrium liquid of posaconazole is nematic-like. Posaconazole glasses can show very high kinetic stability; the isothermal transformation of a 400 nm glass into the supercooled liquid occurs via a propagating front that originates at the free surface and requires ~105 times the structuralmore » relaxation time of the liquid (τα). We also studied the kinetic stability of PVD glasses of itraconazole, which is a structurally similar molecule with equilibrium liquid crystal phases. While itraconazole glasses can be even more anisotropic than posaconazole glasses, they exhibit lower kinetic stability.« less

Authors:
 [1];  [1];  [2];  [1];  [2];  [1]
  1. Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
  2. School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705-2222, USA
Publication Date:
Research Org.:
University of Wisconsin-Madison
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1353393
DOE Contract Number:
SC0002161
Resource Type:
Data
Data Type:
Figures/Plots
Country of Publication:
United States
Availability:
University of Wisconsin-Madison
Language:
English
Subject:
36 MATERIALS SCIENCE; glassy liquid crystals; nematic; Infrared spectroscopy; ellipsometry

Citation Formats

Gomez, Jaritza, Gujral, Ankit, Huang, Chengbin, Bishop, Camille, Yu, Lian, and Ediger, Mark. Nematic-like stable glasses without equilibrium liquid crystal phases. United States: N. p., 2017. Web. doi:10.11578/1353393.
Gomez, Jaritza, Gujral, Ankit, Huang, Chengbin, Bishop, Camille, Yu, Lian, & Ediger, Mark. Nematic-like stable glasses without equilibrium liquid crystal phases. United States. doi:10.11578/1353393.
Gomez, Jaritza, Gujral, Ankit, Huang, Chengbin, Bishop, Camille, Yu, Lian, and Ediger, Mark. Wed . "Nematic-like stable glasses without equilibrium liquid crystal phases". United States. doi:10.11578/1353393. https://www.osti.gov/servlets/purl/1353393.
@article{osti_1353393,
title = {Nematic-like stable glasses without equilibrium liquid crystal phases},
author = {Gomez, Jaritza and Gujral, Ankit and Huang, Chengbin and Bishop, Camille and Yu, Lian and Ediger, Mark},
abstractNote = {We report the thermal and structural properties of glasses of posaconazole, a rod-like molecule, prepared using physical vapor deposition (PVD). PVD glasses of posaconazole can show substantial molecular orientation depending upon the choice of substrate temperature, Tsubstrate, during deposition.Ellipsometry and IR measurements indicate that glasses prepared at Tsubstrate very near the glass transition temperature (Tg) are highly ordered. For these posaconazole glasses, the orientation order parameter is similar to that observed in macroscopically aligned nematic liquid crystals, indicating that the molecules are mostly parallel to one another and perpendicular to the interface. To our knowledge, these are the most anisotropic glasses ever prepared by PVD from a molecule that does not form equilibrium liquid crystal phases. These results are consistent with a previously proposed mechanism in which molecular orientation in PVD glasses is inherited from the orientation present at the free surface of the equilibrium liquid. This mechanism suggests that molecular orientation at the surface of the equilibrium liquid of posaconazole is nematic-like. Posaconazole glasses can show very high kinetic stability; the isothermal transformation of a 400 nm glass into the supercooled liquid occurs via a propagating front that originates at the free surface and requires ~105 times the structural relaxation time of the liquid (τα). We also studied the kinetic stability of PVD glasses of itraconazole, which is a structurally similar molecule with equilibrium liquid crystal phases. While itraconazole glasses can be even more anisotropic than posaconazole glasses, they exhibit lower kinetic stability.},
doi = {10.11578/1353393},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2017},
month = {Wed Feb 01 00:00:00 EST 2017}
}

Dataset:

Save / Share: