Figure 5.

(a) Bright field images of bi-layered hydrogels with varying diffusion times for the second layer ((a-1): 1 min; (a-2): 5 min; (a-3): 10 min). (b) Radius of curvature of bi-layered hydrogels relative to the diffusion time of the second layer. (c) Cross-sectional fluorescence image of a multi-layered hydrogel with the first and second layers, including the interfacial layer. (d) Fluorescence intensity across the multi-layered hydrogel as a function of distance. (e) Thickness measurements of the interfacial layer in each bi-layered hydrogel (BH-3 and BH-5) at 0 and 10 s. (Scale bar: 2 mm).