Main-chain swollen liquid crystal elastomers: A molecular simulation study

We have performed large-scale off-lattice computer simulations in a model system of swollen mainchain liquid-crystalline elastomers, constituted of weakly reticulated soft Gay–Berne chains, investigating both nematic and smectic morphologies. We present isostress Monte Carlo results for temperature-scan and stress–strain experiments, and connect to typical experimental observables, such as sample dimensions, specific heat, deuterium magnetic resonance spectra, and scattered X-ray patterns. We find that the results reproduce the main features of main-chain elastomers, e.g., a pronounced strain-alignment coupling and the existence of two (nematic–isotropic and smectic–nematic) order–disorder phase transitions. The nematic–isotropic transition in our system turns out to be weakly first-order.