Short-chain polymer rigidity due to the Debye process of monohydroxy alcohols

TL;DR

This study provides mechanical evidence for the Debye process in monohydroxy alcohols, revealing polymer-like behavior through rheology experiments, and suggests new non-dielectric methods to explore its microscopic nature.

Contribution

It demonstrates the Debye process's mechanical signature in monohydroxy alcohols, linking it to polymer-like structures using rheology, a novel approach beyond dielectric techniques.

Findings

Mechanical evidence of the Debye process found in monohydroxy alcohols.

Spectral signature similar to small-chain polymers identified.

Estimated molecular weight of supramolecular structures derived.

Abstract

In addition to the ubiquitous structural relaxation of viscous supercooled liquids, monohydroxy alcohols and several other hydrogen-bonded systems display a strong single-exponential electrical low-frequency absorption. So far, this so-called Debye process could be observed only using dielectric techniques. Exploiting a combination of broad-band and high-resolution rheology experiments for three isomeric octanols, unambiguous mechanical evidence for the Debye process is found. Its spectral signature is similar to the viscoelastic fingerprint of small-chain polymers, enabling us to estimate the effective molecular weight for the supramolecular structure formed by the studied monohydroxy alcohols. This finding opens the venue for the application of further non-dielectric techniques directed at unraveling the microscopic nature of the Debye process and for an understanding of this phenomenon in terms of polymer concepts.