Influence of Hydrogen Bonding on the Kinetic Stability of Vapor Deposited Glasses of Triazine Derivatives
File(s)
Date
2017Author
Ediger, Mark
Pellerin, Christian
Lebel, Olivier
Gujral, Ankit
Laventure, Audrey
Publisher
American Chemical Society
Metadata
Show full item recordAbstract
It has recently been established that physical
vapor deposition (PVD) can produce organic glasses with
enhanced kinetic stability, high density, and anisotropic
packing, with the substrate temperature during deposition
(Tsubstrate) as the key control parameter. The influence of
hydrogen bonding on the formation of PVD glasses has not
been fully explored. Herein, we use a high-throughput
preparation method to vapor-deposit three triazine derivatives
over a wide range of Tsubstrate, from 0.69 to 1.08Tg, where Tg is
the glass transition temperature. These model systems are
structural analogues containing a functional group with
different H-bonding capability at the 2-position of a triazine
ring: (1) 2-methylamino-4,6-bis(3,5-dimethyl-phenylamino)-
1,3,5-triazine (NHMe) (H-bond donor), (2) 2-methoxy-4,6-bis(3,5-dimethyl-phenylamino)-1,3,5-triazine (OMe) (H-bond
acceptor), and (3) 2-ethyl-4,6-bis(3,5-dimethyl-phenylamino)-1,3,5-triazine (Et) (none). Using spectroscopic ellipsometry, we
find that the Et and OMe compounds form PVD glasses with relatively high kinetic stability, with the transformation time (scaled
by the α-relaxation time) on the order of 103
, comparable to other highly stable glasses formed by PVD. In contrast, PVD glasses
of NHMe are only slightly more stable than the corresponding liquid-cooled glass. Using IR spectroscopy, we find that both the
supercooled liquid and the PVD glasses of the NHMe derivative show a higher average number of bonded NH per molecule than
that in the other two compounds. These results suggest that H-bonds hinder the formation of stable glasses, perhaps by limiting
the surface mobility. Interestingly, despite this difference in kinetic stability, all three compounds show properties typically
observed in highly stable glasses prepared by PVD, including a higher density and anisotropic molecular packing (as characterized
by IR and wide-angle X-ray scattering)
Subject
Stable glass, hydrogen bonding, vapor deposition, X-Ray scattering, Infrared spectroscopy,Ellipsometry
Permanent Link
http://digital.library.wisc.edu/1793/76412Description
The effect of hydrogen bonding on the properties of vapor deposited glasses is studied.
Citation
Laventure, A., Gujral, A., Lebel, O., Pellerin, C. and Ediger, M.D., 2017. Influence of Hydrogen Bonding on the Kinetic Stability of Vapor-Deposited Glasses of Triazine Derivatives. The Journal of Physical Chemistry B.