A macroscopic constitutive relation for isotropic-genesis, polydomain liquid crystal elastomers

Liquid crystal elastomers (LCEs) are rubber-like solids that incorporate nematic mesogens (stiff rod-like molecules) as a part of their polymer chains. In recent years, isotropic-genesis, polydo-main liquid crystal elastomers (I-PLCEs) has been a topic of both scientific and technological interest due to their intriguing properties such as soft behavior, ability to dissipate energy and stimuli response, as well as the ease with which they can be synthesized. We present a macroscopic or engineering scale constitutive model of the behavior of I-PLCEs. The model implicitly accounts for the complex evolution of the domain patterns and is able to faithfully capture the experimentally observed complex response to multi-axial loading. We describe a multiscale framework that motivates the model, explore various aspects of the model, validate it against experiments, and finally verify and demonstrate a numerical implementation.

Automated summary

Liquid crystal elastomers (LCEs) are rubber-like solids that incorporate nematic mesogens as a part of their polymer chains. Isotropic-genesis, polydo-main liquid crystal elastomers (I-PLCEs) have attracted scientific and technological interest due to their soft behavior, energy dissipation capabilities, stimuli response, and ease of synthesis. In this study, we present a macroscopic constitutive model that accurately captures the complex response of I-PLCEs to multi-axial loading, considering the evolution of domain patterns. We validate the model against experiments and demonstrate its numerical implementation.