Polyamorphism in vapor-deposited 2-methyltetrahydrofuran: A broadband dielectric relaxation study

Jan Philipp Gabriel*, Birte Riechers, Erik Thoms, Anthony Guiseppi-Elie, Mark D. Ediger, Ranko Richert

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review


Depositing a simple organic molecular glass-former 2-methyltetrahydrofuran (MTHF) onto an interdigitated electrode device via physical vapor deposition gives rise to an unexpected variety of states, as revealed by dielectric spectroscopy. Different preparation parameters, such as deposition temperature, deposition rate, and annealing conditions, lead, on the one hand, to an ultrastable glass and, on the other hand, to a continuum of newfound further states. Deposition below the glass transition temperature of MTHF leads to loss profiles with shape parameters and peak frequencies that differ from those of the known bulk MTHF. These loss spectra also reveal an additional process with Arrhenius-like temperature dependence, which can be more than four decades slower than the main structural relaxation peak. At a given temperature, the time constants of MTHF deposited between 120 K and 127 K span a range of more than three decades and their temperature dependencies change from strong to fragile behavior. This polyamorphism involves at least three distinct states, each persisting for a duration many orders of magnitude above the dielectric relaxation time. These results represent a significant expansion of a previous dielectric study on vapor deposited MTHF [B. Riechers et al., J. Chem. Phys. 150, 214502 (2019)]. Plastic crystal states and the effects of weak hydrogen bonding are discussed as structural features that could explain these unusual states.

Original languageEnglish
Article number024502
JournalJournal of Chemical Physics
Issue number2
Publication statusPublished - 14 Jan 2021

Bibliographical note

Funding Information:
This work was supported by the National Science Foundation under Grant No. CHE-1854930.

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