Molecular modeling of liquid crystal elastomers
Seminar Room 1, Newton Institute
Liquid crystal elastomers (LCE) are 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 orientational mesogenic order. As the latter can be controlled by external stimuli such as temperature, electric field, or ultraviolet light, LCE have great potential for application as sensors and actuators.
Here large-scale molecular simulations of swollen main-chain LCE will be presented. The simulated experiments include temperature scans, stress-strain runs, and the application of an external electric field. Our isostress Monte Carlo simulations are capable of reproducing isotropic, nematic and smectic phases, as well as a stress-induced isotropic-to-nematic transition. Moreover, a transversal electric field is seen to induce nematic director rotation resulting in orientational stripe domains. The role of sample swelling has been explored as well.
The simulation output has also been used to connect to typical experimental observables, such as sample dimensions, specific heat, deuterium magnetic resonance spectra, and scattered X-ray patterns.