Fabricating liquid crystal vitrimer actuators far below the normal processing temperature.

Abstract

Liquid crystal vitrimers can be reprocessed, reshaped, welded, and healed due to exchange-reaction-enabled topology changes despite having fully covalently cross-linked network structures. Fabricating liquid crystal (LC) vitrimer actuators is invariably carried out above a characteristic temperature known as the topology freezing transition temperature (Tv). The reason that all exchange-reaction-based operations must be performed above Tv is because the exchange reaction is insignificant below Tv. Here we find that LC vitrimers can be reshaped at temperatures below the measured Tv, whereas non-LC vitrimers cannot. The work here not only makes it possible to create reprogrammable and stable LC vitrimer actuators at low temperatures but also reminds us that both our measurement and understanding of the Tv need further attention to facilitate the use of vitrimers in different areas.