Imine-Based Reactive Mesogen and Its Corresponding Exchangeable Liquid Crystal Elastomer.

To date, exchangeable liquid crystalline elastomers (xLCEs) have been mainly fabricated by combining conventional LCEs with additional exchangeable functional groups in their networks. While conventional LCEs are frequently made from commercially available aromatic-ester reacting mesogens or from mesogens based on a biphenyl core, such reacting monomers are not optimized to fabricating xLCEs whose bond-exchange reaction is fast and clean cut. Here, we develop a fast synthesis route to produce a new type of reactive mesogen based on an aromatic-imine structure that intrinsically enables a fast and stable bond-exchange reaction in the resulting imine-based xLCE.

Exchangeable Liquid Crystalline Elastomers and Their Applications.

This Review presents and discusses the current state of the art in "exchangeable liquid crystalline elastomers", that is, LCE materials utilizing dynamically cross-linked networks capable of reprocessing, reprogramming, and recycling. The focus here is on the chemistry and the specific reaction mechanisms that enable the dynamic bond exchange, of which there is a variety. We compare and contrast these different chemical mechanisms and the key properties of their resulting elastomers.

Rates of transesterification in epoxy-thiol vitrimers.

Vitrimers, an important subset of dynamically crosslinked polymer networks, have many technological applications for their excellent properties, and the ability to be re-processed through plastic flow above the so-called vitrification temperature. We report a simple and efficient method of generating such adaptive crosslinked networks relying on transesterification for their bond exchange by utilising the 'click' chemistry of epoxy and thiols, which also has the advantage of a low glass transition temperature. We vary the chemical structure of thiol spacers to probe the effects of concentration and the local environment of ester groups on the macroscopic elastic-plastic transition.