Opto-regulation for the 2D to 3D transformation of a liquid crystal network membrane

Light loading mode plays essential roles in the deformation morphology of the photosensitive liquid crystal network (LCN) membrane. However, owing to the strong non-linearity of membrane deformation and the constraint effect of membrane boundary, the precise surface pattern control of a LCN membrane through pre-designing the light loading pattern have not been fully carried out. In this article, a second light-engraving strategy is proposed to decouple the local and integral deformation of the LCN membrane, and the accurate opto-regulation of the 2D to 3D pattern transformation could be realized. Firstly, the opto-deformation governing equations for the LCN membrane under nonuniform illumination are established, and solved by the finite difference method. The deformation characteristics of the LCN membrane under nonuniform illumination has been discussed, and the relation between the light loading mode and the spontaneous deformation in the LCN membrane is clarified. Then a second-engraving technology based on the deformed membrane is proposed, and the precise opto-tuning of the 2D to 3D deformation for a LCN membrane is realized. "Robert face" and three-dimensional word printing is presented as example. This work provides theoretical and numerical guidance on the LCN membrane based three dimensional modeling technology.