TY - JOUR
T1 - AC versus DC field effects on the crystallization behavior of a molecular liquid, vinyl ethylene carbonate (VEC)
AU - Duarte, Daniel M.
AU - Richert, Ranko
AU - Adrjanowicz, Karolina
N1 - Copyright:
This record is sourced from MEDLINE/PubMed, a database of the U.S. National Library of Medicine
PY - 2021/1/6
Y1 - 2021/1/6
N2 - Using electric fields to control crystallization processes shows a strong potential for improving pharmaceuticals, but these field effects are not yet fully explored nor understood. This study investigates how the application of alternating high electric fields can influence the crystallization kinetics as well as the final crystal product, with a focus on the possible difference between alternating (ac) and static (dc) type fields applied to vinyl ethylene carbonate (VEC), a molecular system with field-induced polymorphism. Relative to ac fields, static electric fields lead to more severe accumulation of impurity ions near the electrodes, possibly affecting the crystallization behavior. By tuning the amplitude and frequency of the electric field, the crystallization rate can be modified, and the crystallization outcome can be guided to form one or the other polymorph with high purity, analogous to the findings derived from dc field experiments. Additionally, it is found that low-frequency ac fields reduce the induction time, promote nucleation near Tg, and affect crystallization rates as in the dc case. Consistency is also observed for the Avrami parameters n derived from ac and dc field experiments. Therefore, it appears safe to conclude that ac fields can replicate the effects seen using dc fields, which is advantageous for samples with mobile charges and the resulting conductivity.
AB - Using electric fields to control crystallization processes shows a strong potential for improving pharmaceuticals, but these field effects are not yet fully explored nor understood. This study investigates how the application of alternating high electric fields can influence the crystallization kinetics as well as the final crystal product, with a focus on the possible difference between alternating (ac) and static (dc) type fields applied to vinyl ethylene carbonate (VEC), a molecular system with field-induced polymorphism. Relative to ac fields, static electric fields lead to more severe accumulation of impurity ions near the electrodes, possibly affecting the crystallization behavior. By tuning the amplitude and frequency of the electric field, the crystallization rate can be modified, and the crystallization outcome can be guided to form one or the other polymorph with high purity, analogous to the findings derived from dc field experiments. Additionally, it is found that low-frequency ac fields reduce the induction time, promote nucleation near Tg, and affect crystallization rates as in the dc case. Consistency is also observed for the Avrami parameters n derived from ac and dc field experiments. Therefore, it appears safe to conclude that ac fields can replicate the effects seen using dc fields, which is advantageous for samples with mobile charges and the resulting conductivity.
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U2 - 10.1039/d0cp05290f
DO - 10.1039/d0cp05290f
M3 - Article
C2 - 33325478
AN - SCOPUS:85100280817
SN - 1463-9076
VL - 23
SP - 498
EP - 505
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 1
ER -