Abstract

Liquid crystal elastomers (LCEs) are responsive multifunctional materials that combine the flexibility of polymeric networks with the self-organisation of liquid crystals. Due to their complex molecular architecture, they can exhibit dramatic spontaneous deformations and phase transitions, which are reversible and repeatable under external stimuli, such as heat, light, solvents, and electric or magnetic fields. These properties could be harnessed for a variety of advanced technological applications, including soft actuators, sensors, biomedical engineering and renewable energy. An important problem for both applications and our fundamental understanding of LCEs is their instability under large strains, as this can be useful in actuation, sensing, or patterning. The goal is then to identify parameter values at which a bifurcation emerges, and how these values change with external stimuli, such as temperature, or loads. Constitutive parameters of real manufactured materials have also an inherent variation that needs to be taken into account. In this talk, I will present an overview of instabilities occurring in nematic elastomers, and examine the contribution of nematic order and fluctuating model parameters that follow probability laws. This mechanical analysis may lead to a more effective material characterisation of LCEs.