Assist. Prof. Dr. Gregor Skačej (FMF): Gay-Berne liquid crystal elastomers: biaxiality, photoactuation, and caloric effects

Liquid crystal elastomers (LCE) are soft functional materials consisting of weakly crosslinked polymer networks with embedded liquid crystalline (mesogenic) molecules. Consequently, LCE are characterized by a pronounced coupling between macroscopic strain and mesogenic orientational order. As the latter can be controlled by external stimuli such as temperature changes, electric field, or ultraviolet light, LCE can be employed in different applications, e.g., as sensors and actuators.
This talk will present large-scale molecular simulations of swollen main-chain LCE, with mesogenic molecules represented by coarse-grained Gay-Berne ellipsoids, to elucidate some recent issues. These include the onset of the elusive biaxial phase, photoactuation in azobenzene-based systems, and the elastocaloric effect for cooling and heat-pump applications. The extensive simulation output will be used to predict selected experimental observables like sample shape, photoinduced stress, deuterium magnetic resonance spectra, scattered X-ray patterns, specific heat, and elastocaloric responsivity.
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