Continuous Isotropic-Nematic transition in compressed rod-like based nanocolloid

TL;DR

This study demonstrates that nanocolloids of rod-like molecules with BaTiO3 nanoparticles exhibit a continuous isotropic-nematic transition under pressure, contrasting with traditional models predicting a discontinuous transition.

Contribution

It provides experimental evidence of a pressure-induced continuous I-N transition in nanocolloids, challenging existing theoretical predictions of a discontinuous transition.

Findings

Continuous I-N transition observed in nanocolloids with 0.1% nanoparticles.

Enormous dielectric constant values in nematic phase.

Detection of pretransitional fluctuations affecting dielectric properties.

Abstract

Landau - de Gennes mean field model predicts the discontinuous transition for the Isotropic - Nematic transition, associated with uniaxial and quadrupolar order parameter in three dimensions. This report shows pressure-related dielectric studies for rod-like nematogenic pentylcyanobiphenyl (5CB) and its nanocolloids with BaTiO3 nanoparticles. The scan of dielectric constant revealed the continuous I-N transition in a compressed nanocolloid with a tiny amount of nanoparticles (x=0.1%). For the nematic phase in 5CB and its x=1% nanocolloid the enormous values of dielectric constant and the bending-type long-range pretransitional behavior were detected. The 'shaping' influence of pretransitional fluctuations was also detected for the ionic-related contribution to dielectric permittivity in the isotropic phase. For the high-frequency relaxation domain, this impact was tested for the primary relaxation time and the translational-orientaional decoupling.