Topographic change of the shape memory polymer substrates.

Optical micrographs of an active wrinkling shape memory polymer substrate (A) before and (B) after completion of formation of the nano-wrinkled topography employed to examine the temporal evolution of mouse fibroblast polarization. The direction of programmed tensile strain in (A) is horizontal, and, thus, the direction of wrinkle formation in (B) is vertical, as indicated by the double-headed arrow. Scale bar is 50 μm.