Hierarchical Multi-Step Folding of Polymer Bilayers

A highly complex multi-step folding of isotropic stimuli-responsive polymer bilayers resulting in a variety of 2D and 3D structures is reported. Experimental observations allow determination of empirical rules, which can be used to direct the folding of polymer films in a predictable manner. In particular, it is demonstrated that these rules can be used for the design of a 3D pyramid. The understanding and know-how attained in this study allow the very simple design of highly complex, self-folding 3D objects and open new horizons for 3D patterning, important for the design of microfluidic devices, biomaterials, and soft electronics.