Inhomogeneous stretch induced patterning of molecular orientation in liquid crystal elastomers

Liquid crystal elastomer (LCE) is soft active material, which can have large deformation when subjected to various external stimuli. Due to the coupling between the orientation of liquid crystal (LC) molecules in the elastomer and the deformation of LCEs, mechanical behaviors of LCEs can be significantly modified by manipulating LC molecular orientation field in the material. In the letter, we demonstrate, for the first time, that inhomogeneous and anisotropic stretch field can be used to pattern LC molecular orientation in the LCE during its synthesis. We further show that different active deformation modes can be realized in LCE sheets with different patterns of LC molecules. The method developed in the letter to pattern LC molecular orientation field in the LCE is facile and effective, which may find wide applications in fabricating programmable materials and structures. (C) 2015 Elsevier Ltd. All rights reserved.