Isolating the impact of network strand length dispersity on liquid crystal elastomer phase transitions

Project Description

Liquid crystal elastomers (LCEs) are a class of polymeric network that combine the elastic properties of rubber with the anisotropic properties of crystals. The materials undergo reversible, theoretically first-order phase transitions from an ordered nematic state to a disordered isotropic state in response to external stimuli. Through this phase transition and the coupling between nematic order and the polymer backbone, LCEs exhibit remarkable properties, including actuation and the elastocaloric effect. However, defects within the network broaden the nematic-to-isotropic transition, limiting the performance of LCE properties. Network strand length dispersity stands out as a key contributor to this broadening, arising from the high dispersity of the step-growth synthesis procedure commonly used to fabricate LCEs. We propose using a fractionation approach to synthesize LCEs from low-dispersity polymers, enabling a systematic study of the impact of dispersity on LCE phase transitions.