# Fluorine-Assisted Self-Assembly Triggers Peculiarities in Molecular Dynamics of a Polar Glass-Former

## TL;DR

This paper shows how fluorine-assisted self-assembly disrupts typical glass-forming dynamics in a polar liquid.

## Contribution

A polar liquid is shown to break established glass-forming rules due to fluorine-assisted self-assembly.

## Key findings

- The liquid exhibits extremely low dielectric strength and Debye-like dielectric spectra.
- The Kirkwood correlation factor is much below unity, and structural relaxation accelerates significantly.
- Fluorine-assisted self-assembly is confirmed via Raman and XRD measurements.

## Abstract

Condensed matter physics has long struggled to obtain
a comprehensive
picture of the liquid-glass transition. Consequently, over the years,
universal manifestations of glassy and supercooled dynamics have been
established, including a correlation between the static dielectric
constant (Δε) and relaxation stretching (βKWW), as well as βKWW and Kirkwood correlation factor
(g
K), or deviation degree from Arrhenius
behavior of structural relaxation times quantified by dynamic fragility
(m
P). Herein, we report a simple, highly
polar liquid that breaks all of these rules established for glass-forming
liquids. We show that the fluorine-assisted self-assembly, confirmed
by temperature-dependent Raman and XRD measurements, brings peculiarities
in relaxation dynamics, that is, extremely low dielectric strength,
Debye-like shape of dielectric permittivity spectra, g
K much below unity, and enormous acceleration of structural
relaxation times and viscosity at T = T
g + 20 K. All these peculiarities reveal a strong effect
of molecular self-assembly on the dynamics of glass-forming systems.