Self-folding of three-dimensional hydrogel microstructures

J Phys Chem B. 2005 Dec 15;109(49):23134-7. doi: 10.1021/jp054341g.


This letter describes the fabrication of three-dimensional particulate-like hydrogel microstructures using a combination of soft lithography and volume expansion induced self-folding. Bilayer structures are produced by solvent casting and photocuring of liquid resins. They curl into three-dimensional (3D) structures upon contacting with water due to differential swelling of the two layers. The curvature can be controlled by adjusting the polymer composition of the primary swelling layer. A simple semiempirical mathematical model is used to predict this self-folding behavior. By designing the two-dimensional (2D) shapes of the bilayers, this technique can lead to complicated 3D microstructures.