ABSTRACT
Weakly cross-linked polymeric networks-elastomers-with embedded liquid crystalline units represent a novel class of functional soft materials. They couple the elastic properties of rubbers with the orientational anisotropy of liquid crystals [1]. Accordingly, liquid crystal elastomers (LCE) are characterized by pronounced responsiveness to external stimuli such as temperature variation, application of external fields, mechanical or electric, or irradiation with ultraviolet (UV) light, that can be exploited, for example, for the construction of new actuator and sensor devices [2]. The design of these devices relies on the (at least qualitative) understanding of structural features and system behavior on the microscopic level. On the fundamental side, irregular cross-links in a LCE network result in quenched disorder similar to that observed in spin glasses with magnetic impurities [3] or random anisotropy [4]. Hence, LCE have become interesting both from theoretical and application point of view. Theoretically, LCE have been described at the continuum level by anisotropic rubber elasticity [1] and by phenomenological Landau-type approaches [5-7]. Finiteelement continuum computer simulations have been used to study various phenomena in macroscopic LCE samples [8].Along with the existing continuum descriptions that are based on a specific free energy expression, microscopic molecular-level or coarsegrained computer simulation studies can provide significant complementary insight
into LCE behavior. Unfortunately, the modeling and simulation of these complex systems is not straightforward and a number of attempts have been made so far in the field of microscopic computer simulation of LCE.According to the level of detail treated in the modeling, they can be classified into three groups: (1) lattice models, (2) anisotropic beads and spring models, and (3) atomistic models.
