TY - JOUR
T1 - Frequency of the AC Electric Field Determines How a Molecular Liquid Crystallizes
AU - Duarte, Daniel M.
AU - Richert, Ranko
AU - Adrjanowicz, Karolina
N1 - Funding Information:
We thank Zaneta Wojnarowska for determining the viscosity of VEC. Part of this work was supported by the National Science Foundation under grant no. DMR-1904601. Financial support from the National Science Centre within the framework of the SONATA BIS project (grant no. 2017/26/E/ST3/00077) is greatly acknowledged.
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/5/21
Y1 - 2020/5/21
N2 - The ability to control crystallization is of central importance to many technologies and pharmaceutical materials. Electric fields have been shown to impact crystallization, but little is known about the mechanism of such effects. Here we report on our observations of how the frequency of an external electric (ac) field changes the crystallization rate and the partitioning into distinct polymorphs of vinylethylene carbonate. We find that the field effects are pronounced only for frequencies below a certain threshold, which is orders of magnitude below that characterizing molecular orientation but consistent with the reorientation of polar crystal nuclei of radius r < 3 nm. We conclude that the electric field opens an additional nucleation pathway by lowering the free-energy barrier to form a polymorph that melts at a temperature ∼20 K below that of the ordinary crystal. This lower melting polymorph is not obtained at zero electrical field.
AB - The ability to control crystallization is of central importance to many technologies and pharmaceutical materials. Electric fields have been shown to impact crystallization, but little is known about the mechanism of such effects. Here we report on our observations of how the frequency of an external electric (ac) field changes the crystallization rate and the partitioning into distinct polymorphs of vinylethylene carbonate. We find that the field effects are pronounced only for frequencies below a certain threshold, which is orders of magnitude below that characterizing molecular orientation but consistent with the reorientation of polar crystal nuclei of radius r < 3 nm. We conclude that the electric field opens an additional nucleation pathway by lowering the free-energy barrier to form a polymorph that melts at a temperature ∼20 K below that of the ordinary crystal. This lower melting polymorph is not obtained at zero electrical field.
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U2 - 10.1021/acs.jpclett.0c01002
DO - 10.1021/acs.jpclett.0c01002
M3 - Article
C2 - 32352784
AN - SCOPUS:85085263500
SN - 1948-7185
VL - 11
SP - 3975
EP - 3979
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 10
ER -