Figure 1: Conceptual schematic and experimental realization of the self-assembly of differentially crosslinked and conditioned SU-8 films.

(a) A schematic showing the CLG formation within a low ultraviolet exposed SU-8 film, which results in a stress (σ) gradient along the film thickness (d), on conditioning of the film in acetone to remove un-crosslinked material. (b) When water is added, the film is de-solvated and the less crosslinked side undergoes greater compression, causing the film to curve. (c) Immersion in acetone re-solvates the film, causing the film to flatten. (d) Fluorescence images of an array of flower-shaped structures that (top) reversibly curved on de-solvation and (bottom) flattened on re-solvation. Scale bars are 100 μm.