# The Impact of Nanoparticles on Previtreous Behavior: Glass-Forming Nematogenic E7 Mixture-Based Nanocolloids

## TL;DR

This study explores how nanoparticles affect the behavior of a liquid crystal mixture near its glass transition, revealing unique dielectric and phase transition properties.

## Contribution

The paper introduces a novel heuristic model linking the glass transition to a hidden near-critical phase transition without symmetry change.

## Key findings

- Nanoparticles induce critical-like changes in the dielectric constant near the glass transition temperature.
- The MYEGA equation and Drozd-Rzoska relation effectively describe the dynamic properties of the nanocolloids.
- LC molecules show permanent alignment in the nematic phase due to nanoparticle influence.

## Abstract

This report discusses the impact of nanoparticles on glass-forming systems composed of a liquid crystalline (LC) mixture E7 and paraelectric BaTiO3 particles (d≈50 nm, globular), tested via broadband dielectric spectroscopy. In the isotropic phase, critical changes in the dielectric constant are shown. They are related to the weakly discontinuous nature of the isotropic–nematic transition. In the nematic phase, two primary relaxation times/processes and DC electric conductivity are considered, down to the glass temperature Tg. The prevalence of portrayals via the ‘double exponential’ MYEGA equation and the critical & activated Drozd-Rzoska relation for dynamic properties are shown. For the primary loss curve, critical-like changes of its maximum (peak) are evidenced: εpeak″∝1/T−Tg* for Tg<T<Tg+25 K, where Tg*<Tg denotes the extrapolated singular temperature. Dielectric constant monitoring revealed the permanent arrangement of rod-like LC molecules by nanoparticles’ endogenic impact in the nematic phase. The heuristic model regarding this unique behavior is presented. It considers a hypothetical link between the glass transition and a hidden near-critical discontinuous phase transition, uniquely avoiding a symmetry change. The uniaxiality of LC molecules enables the detection of critical-like features when approaching the glass transition, hypothetically associated with a specific ‘amorphous’ phase transition.