  Rheodielectric spectroscopy is employed, for the first time, to investigate
the effect of external shear on the Debyelike relaxation of a model monohydroxy
alcohol, i.e., the 2-ethyl-1-hexanol (2E1H). Shear deformation leads to strong
acceleration in the structural relaxation, the Debye relaxation, and the
terminal relaxation of 2E1H. Moreover, the shear-induced reduction in
structural relaxation time, tau_alpha, scales quadratically with that of Debye
time, tau_D, and the terminal flow time, tau_f, suggesting a relationship of
tau_D*tau_D~tau_alpha. Further analyses reveal tau_D*tau_D/tau_alpha of 2E1H
follows Arrhenius temperature dependence that applies remarkably well to many
other monohydroxy alcohols with different molecular sizes, architectures, and
alcohol types. These results cannot be understood by the prevailing transient
chain model and suggest a H-bonding breakage facilitated sub-supramolecular
reorientation as the origin of Debye relaxation of monohydroxy alcohols, akin
to the molecular mechanism for the terminal relaxation of unentangled living
polymers
