High electric fields elucidate the hydrogen-bonded structures in 1-phenyl-1-propanol

High electric fields are applied to illuminate the role of hydrogen bonding in the dielectric relaxation of 1-phenyl-1-propanol (1P1P). Unlike many other monohydroxy alcohols, 1P1P is not associated with a strong distinct Debye loss peak, which would indicate chain-like hydrogen-bonded structures. We exploit the feature that a high field induced enhancement of the dielectric constant indicates a shift of the thermodynamic equilibrium towards more polar (e.g., chain-like) structures. This so-called 'chemical effect' rests on a field-induced lowering of the free energy of the more polar species, thus shifting the equilibrium towards a higher dielectric constant. We demonstrate that an external electrical field of E-B = 245 kV cm(-1) increases the amplitude of the Debye peak, whereas that of the remaining loss profile remains constant. This indicates the coexistence of chain-like and less polar structures in supercooled 1P1P and helps to discriminate the Debye process from the signature of the primary structural relaxation. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study uses high electric fields to investigate the role of hydrogen bonding in the dielectric relaxation of 1-phenyl-1-propanol (1P1P), demonstrating that an external electrical field can shift the thermodynamic equilibrium towards more polar structures. The coexistence of chain-like and less polar structures in supercooled 1P1P is also shown, helping to distinguish the Debye process from the primary structural relaxation.