Nanoparticle-controlled glassy dynamics in nematogen-based nanocolloids.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Physical Chemistry

Background:

• Liquid crystals exhibit unique phase transitions and ordering phenomena.
• Nanoparticles can significantly influence the properties of liquid crystal hosts.
• Understanding these interactions is crucial for developing advanced materials.

Purpose of the Study:

• To investigate the impact of BaTiO_{3} nanoparticles on the dielectric properties and dynamics of pentylcyanobiphenyl (5CB) liquid crystals.
• To study the behavior of these nanocolloids across a wide temperature range, including the supercooled nematic phase.
• To develop a theoretical model explaining the observed phenomena.

Main Methods:

• Broad-band dielectric spectroscopy was employed to study 5CB-based nanocolloids.
• Measurements were conducted over an extreme temperature range (∼150 K).
• Analysis included distortion-sensitive analysis and a model combining Landau-de Gennes and Imry-Ma approaches.

Main Results:

• BaTiO_{3} nanoparticles strongly influence the dynamics and uniaxial ordering of 5CB.
• A unique pretransitional effect for dielectric constant was observed in the supercooled nematic phase.
• Super-Arrhenius dynamics with critical-like behavior and translational-orientational decoupling were detected in the isotropic phase.
• The results were linked to heterogeneities and prenematic fluctuations.

Conclusions:

• BaTiO_{3} nanoparticles induce significant changes in liquid crystal behavior.
• The study provides insights into complex dynamics and ordering in nanocolloids.
• The developed model helps explain the interplay between nanoparticles and liquid crystal phases.