Dynamic Theory of Polydomain Liquid Crystal Elastomers

Area of Science:

• Materials Science
• Polymer Physics
• Soft Matter Physics

Background:

• Liquid crystal elastomers (LCEs) exhibit unique properties due to the interplay between polymer networks and liquid crystalline phases.
• Disordered polydomain structures are commonly observed in LCEs cooled into the nematic phase without prior alignment.
• These structures are often attributed to quenched disorder within the cross-linked polymer network.

Purpose of the Study:

• To investigate the role of dynamic processes during the isotropic-nematic transition in the formation of polydomain structures in LCEs.
• To propose an alternative mechanism for polydomain formation beyond quenched disorder.
• To theoretically model the dynamics of the nematic phase transition in LCEs.

Main Methods:

• Development of a theoretical model for the isotropic-nematic transition dynamics in LCEs.
• Analysis of the transition dynamics using principles analogous to the Cahn-Hilliard equation for phase separation.
• Mathematical derivation of the characteristic length scale of the induced polydomain structures.

Main Results:

• The study demonstrates that the dynamics of the isotropic-nematic transition can inherently induce polydomain structures.
• A characteristic length scale for these dynamically induced polydomains is predicted.
• The proposed mechanism offers an alternative explanation for polydomain formation, complementing the quenched disorder hypothesis.

Conclusions:

• The dynamics of the nematic phase transition play a crucial role in the formation of polydomain structures in unaligned LCEs.
• This dynamic mechanism provides a new perspective on the origins of disorder in LCEs.
• The findings have implications for controlling the microstructure and properties of LCE materials.