Related Experiment Video
Updated: Aug 14, 2026

Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Origin of shear-induced phase transitions in melts of liquid-crystal polymers
1Laboratoire Léon Brillouin (CEA-CNRS), Ce-Saclay, 91190 Gif-sur-Yvette Cédex, France. noirez@llb.saclay.cea.fr
Abstract:
Flow induced mechanical properties are often coupled with instabilities, spurt effects, or induced phase transitions. Recent studies have revealed that side-chain liquid crystal polymers exhibit typically shear-induced phases inside the isotropic (nonmesomorphic) liquid state. We present an experimental approach which brings a new understanding for nonlinear flow behaviors. The strategy consists in comparing the critical times issued from the flow behavior of a liquid-crystal polymer to the equilibrium orientational-order relaxation time was characterized. We demonstrate that shear-induced phases do not originate from a flow coupling to conventional orientational order parameter fluctuations. It does not also correspond to a direct coupling with the viscoelastic terminal time, leading to the conclusion that an additional relaxation process takes place with time scales longer than the terminal time. The identification of a low-frequency elastic plateau by viscoelastic measurements corroborates this conclusion.
Related Concept Videos
Polymer Classification: Crystallinity
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Phase Transitions: Melting and Freezing
Phase Transitions
Phase Transitions
Classification and Mechanical Properties of Synthetic Polymers
Polymer Classification: Stereospecificity

